WEBVTT 00:00:00.000 --> 00:00:04.620 Imagine walking through the dense, muddy forests 00:00:04.620 --> 00:00:08.599 of 1840s Ohio. You're hacking your way through 00:00:08.599 --> 00:00:11.000 this incredibly thick underbrush. Oh, and the 00:00:11.000 --> 00:00:13.460 mosquitoes are just absolutely swarming everywhere. 00:00:13.480 --> 00:00:16.559 Right, exactly. And you finally decide to cut 00:00:16.559 --> 00:00:19.980 down this massive, maybe 800 -year -old oak tree 00:00:19.980 --> 00:00:22.140 just to clear a path. Just to get your bearings, 00:00:22.160 --> 00:00:24.420 yeah. Yeah. But when the trunk finally falls 00:00:24.420 --> 00:00:26.839 and the dust clears, you look down and you realize 00:00:26.839 --> 00:00:29.829 the hill this ancient tree was growing on. It 00:00:29.829 --> 00:00:32.409 isn't a natural hill at all. No, it's an earthen 00:00:32.409 --> 00:00:35.149 wall. It's a wall. And as you trace that wall 00:00:35.149 --> 00:00:39.490 through, like, miles of untamed forest, you discover 00:00:39.490 --> 00:00:42.130 it forms this perfectly engineered geometric 00:00:42.130 --> 00:00:45.850 octagon built by some entirely vanished civilization. 00:00:45.890 --> 00:00:47.929 I mean, it completely shatters your understanding 00:00:47.929 --> 00:00:50.130 of the landscape. Suddenly, you're standing inside 00:00:50.130 --> 00:00:53.689 a prehistoric monument of just staggering proportions. 00:00:53.750 --> 00:00:55.429 And you have absolutely no idea who built it. 00:00:55.530 --> 00:00:57.689 Right. Who built it, when they built it, or, 00:00:57.689 --> 00:01:00.619 you know, why. Well, welcome to another deep 00:01:00.619 --> 00:01:02.579 dive into the source material. We are so glad 00:01:02.579 --> 00:01:04.079 you are here with us today. Yeah, thanks for 00:01:04.079 --> 00:01:06.799 joining us. Today we are opening up a text that 00:01:06.799 --> 00:01:09.659 is, well, it's essentially the holy grail of 00:01:09.659 --> 00:01:12.079 American archaeology. It's called Ancient Monuments 00:01:12.079 --> 00:01:14.840 of the Mississippi Valley. Written by E .G. Squire 00:01:14.840 --> 00:01:18.140 and A .H. Davis. Right. Published back in 1848. 00:01:18.400 --> 00:01:21.879 And this book is so foundational that it was 00:01:21.879 --> 00:01:24.900 literally the very first volume ever published 00:01:24.900 --> 00:01:26.939 in the Smithsonian Contributions to Knowledge 00:01:26.939 --> 00:01:29.140 series. Which is really a testament to the sheer 00:01:29.140 --> 00:01:31.480 weight of this work. Before this book, there 00:01:31.480 --> 00:01:33.739 really wasn't a scientific discipline of archaeology 00:01:33.739 --> 00:01:36.459 on this continent. Not at all. This text completely 00:01:36.459 --> 00:01:38.799 set the baseline. So our mission today for you 00:01:38.799 --> 00:01:42.200 is to explore the breathtaking scale and the 00:01:42.200 --> 00:01:44.780 deep mysteries of these ancient earthworks of 00:01:44.780 --> 00:01:47.420 North America. Yeah. But crucially, And this 00:01:47.420 --> 00:01:49.540 is the really important part. We are going to 00:01:49.540 --> 00:01:51.859 focus on how Squire and Davis actually pulled 00:01:51.859 --> 00:01:54.700 this off. Yeah, the methodology is wild. It is. 00:01:55.019 --> 00:01:56.920 We're going to look at how they pioneered rigorous 00:01:56.920 --> 00:02:00.540 field surveys and ensured strict scientific accuracy 00:02:00.540 --> 00:02:03.840 in an era that was, frankly, completely dominated 00:02:03.840 --> 00:02:07.560 by wild myths and armchair speculation. And we 00:02:07.560 --> 00:02:09.780 really need to understand the climate of the 00:02:09.780 --> 00:02:13.780 1840s to appreciate their achievement. Because, 00:02:13.900 --> 00:02:16.699 you know, as the American frontier pushed westward 00:02:16.699 --> 00:02:20.159 and these massive, inexplicable structures of 00:02:20.159 --> 00:02:22.020 Earth were being revealed. I mean, we're talking 00:02:22.020 --> 00:02:25.479 thousands of mounds. Thousands. Giant earthen 00:02:25.479 --> 00:02:28.039 walls, perfect circles covering hundreds of acres. 00:02:28.199 --> 00:02:30.599 People's imaginations were just running completely 00:02:30.599 --> 00:02:33.580 wild. OK, let's unpack this. Yeah. Because the 00:02:33.580 --> 00:02:36.340 level of speculation was Well, it was off the 00:02:36.340 --> 00:02:38.900 charts. You had popular books and newspaper articles 00:02:38.900 --> 00:02:41.960 claiming these mounds were built by, like, ancient 00:02:41.960 --> 00:02:44.180 giants. Right, or the lost tribes of Israel. 00:02:44.360 --> 00:02:46.939 Yes, or wandering Hindus. Some people even claim 00:02:46.939 --> 00:02:49.020 they were built by refugees from the lost continent 00:02:49.020 --> 00:02:51.560 of Atlantis. I mean, it sounds funny to us now, 00:02:51.580 --> 00:02:54.199 but this was serious public discourse. Because 00:02:54.199 --> 00:02:56.240 there was this underlying prejudice, right? This 00:02:56.240 --> 00:02:58.379 idea that the Native American tribes currently 00:02:58.379 --> 00:03:00.639 living in the region couldn't possibly have engineered 00:03:00.639 --> 00:03:03.340 these structures. Exactly. So 19th century society 00:03:03.340 --> 00:03:06.319 just started inventing these incredibly romantic, 00:03:06.680 --> 00:03:09.599 fabulous origin stories to explain it away. And 00:03:09.599 --> 00:03:12.240 that is exactly where the newly formed Smithsonian 00:03:12.240 --> 00:03:15.639 Institution comes into play. James Smithson, 00:03:15.740 --> 00:03:18.120 who was an English scientist, he had left his 00:03:18.120 --> 00:03:21.370 fortune to the United States. to found an institution 00:03:21.370 --> 00:03:24.189 for the, quote, increase and diffusion of knowledge 00:03:24.189 --> 00:03:27.349 among men. Right. But when the Smithsonian was 00:03:27.349 --> 00:03:29.849 actually established, they had a real problem. 00:03:29.969 --> 00:03:32.909 They had to decide what actually constituted 00:03:32.909 --> 00:03:34.889 knowledge. Like, how do you filter out the giants 00:03:34.889 --> 00:03:37.620 and the Atlanteans? You do it by creating an 00:03:37.620 --> 00:03:40.319 uncompromising standard of evidence. The Smithsonian 00:03:40.319 --> 00:03:43.479 laid down some incredibly strict rules for publication. 00:03:43.659 --> 00:03:46.240 Like really strict. Oh yeah. For a memoir to 00:03:46.240 --> 00:03:48.599 be published by them, it had to rest entirely 00:03:48.599 --> 00:03:51.319 on original research. It had to provide a positive 00:03:51.319 --> 00:03:53.419 addition to human knowledge. And most importantly 00:03:53.419 --> 00:03:56.479 for our story today, absolutely all unverified 00:03:56.479 --> 00:03:59.400 speculations had to be rejected. Tossed out completely. 00:03:59.840 --> 00:04:02.000 And what's fascinating here is that the Smithsonian 00:04:02.000 --> 00:04:04.780 didn't just take Squire and Davis's word for 00:04:04.780 --> 00:04:07.610 their findings. They submitted the manuscript 00:04:07.610 --> 00:04:10.849 to a rigorous peer review commission set up by 00:04:10.849 --> 00:04:13.689 the American Ethnological Society. And this commission 00:04:13.689 --> 00:04:16.230 included some serious heavyweights of the era, 00:04:16.889 --> 00:04:19.029 like Albert Gallatin, the former secretary of 00:04:19.029 --> 00:04:20.930 the treasury. A brilliant scholar in his own 00:04:20.930 --> 00:04:23.550 right. And Gallatin and the committee reviewed 00:04:23.550 --> 00:04:26.449 the work and explicitly praised Squire and Davis 00:04:26.449 --> 00:04:28.910 for their love of truth. I love that phrase, 00:04:29.089 --> 00:04:32.069 love of truth. Right. They noted that the authors 00:04:32.069 --> 00:04:35.899 completely eschewed the what they called fondness 00:04:35.899 --> 00:04:38.639 for the marvelous, which had plagued literally 00:04:38.639 --> 00:04:41.439 every other piece of writing on Western antiquities 00:04:41.439 --> 00:04:44.019 up to that point. So to get that kind of praise, 00:04:44.220 --> 00:04:46.560 Squire and Davis had to make a vow before they 00:04:46.560 --> 00:04:49.160 even stepped foot into the field. They promised 00:04:49.160 --> 00:04:52.100 to abandon all preconceived notions. They decided 00:04:52.100 --> 00:04:56.040 to start de novo from scratch. Yeah, they approached 00:04:56.040 --> 00:04:58.139 these monuments as if nothing had ever been written 00:04:58.139 --> 00:05:01.100 about them before. No giants, no lost tribes. 00:05:01.240 --> 00:05:04.050 Yeah, just. dirt, geometry, and whatever the 00:05:04.050 --> 00:05:06.490 empirical evidence told them. Because the Smithsonian's 00:05:06.490 --> 00:05:08.990 rules forced them to rely entirely on what they 00:05:08.990 --> 00:05:11.329 could measure, weigh, and map. Right, if they 00:05:11.329 --> 00:05:13.129 couldn't mechanically verify it. It didn't go 00:05:13.129 --> 00:05:15.930 in the book, period. But, okay, that raises a 00:05:15.930 --> 00:05:19.459 massive logistical nightmare. Because how exactly 00:05:19.459 --> 00:05:22.839 do you map a prehistoric civilization when all 00:05:22.839 --> 00:05:26.100 that is left are overgrown piles of dirt hidden 00:05:26.100 --> 00:05:29.279 under centuries of old growth forest? It's incredibly 00:05:29.279 --> 00:05:31.439 difficult. You can't just stand on a hill and 00:05:31.439 --> 00:05:33.939 sketch what you see. The sight lines are completely 00:05:33.939 --> 00:05:36.240 blocked by trees. Right, you can't see 50 feet 00:05:36.240 --> 00:05:38.800 in front of you, so you have to invent a methodology 00:05:38.800 --> 00:05:41.399 for the field. You have to put boots on the ground 00:05:41.399 --> 00:05:43.480 and rely on the art of the scientific survey. 00:05:43.899 --> 00:05:46.879 And their methodology was elegant in its simplicity? 00:05:47.360 --> 00:05:50.680 but incredibly demanding in its physical execution. 00:05:50.939 --> 00:05:53.300 Very demanding. They relied exclusively on the 00:05:53.300 --> 00:05:55.720 surveyor's compass, the measuring line, and the 00:05:55.720 --> 00:05:58.199 rule. And we should talk about the sheer physical 00:05:58.199 --> 00:06:01.759 reality of using those tools in the 1840s wilderness. 00:06:02.279 --> 00:06:04.319 Because a surveyor's compass isn't some little 00:06:04.319 --> 00:06:06.240 plastic thing you hold in the palm of your hand. 00:06:06.420 --> 00:06:09.879 Oh, no. It's a heavy brass instrument. It's mounted 00:06:09.879 --> 00:06:12.519 on a tripod. It has these sighting vanes. And 00:06:12.519 --> 00:06:14.579 the measuring line was often a Gunter's chain, 00:06:14.620 --> 00:06:16.540 right? Yes, a literal heavy metal chain that 00:06:16.540 --> 00:06:18.860 you had to physically drag through the mud. Over 00:06:18.860 --> 00:06:22.579 massive tree roots, across uneven terrain, up 00:06:22.579 --> 00:06:25.639 and down hills. It's exhausting work. And there 00:06:25.639 --> 00:06:28.980 is absolutely no eyeballing allowed, no estimating 00:06:28.980 --> 00:06:31.800 distances by, you know, just pacing them out. 00:06:32.279 --> 00:06:35.379 Every single angle, every single length was mechanically 00:06:35.379 --> 00:06:37.519 verified. Which brings us to one of the most 00:06:37.519 --> 00:06:39.480 remarkable parts of their survey, which is the 00:06:39.480 --> 00:06:42.259 circle tests. Oh, this is so cool. So Squire 00:06:42.259 --> 00:06:44.360 and Davis were looking at these massive circular 00:06:44.360 --> 00:06:47.319 earthworks, right? And some of them are a mile 00:06:47.319 --> 00:06:49.560 in circumference. Huge. And they needed to know 00:06:49.560 --> 00:06:53.160 scientifically, are these actually true circles 00:06:53.160 --> 00:06:57.199 or are they just rough blob -like loops that 00:06:57.199 --> 00:06:59.500 happen to look roundish to the naked eye? To 00:06:59.500 --> 00:07:01.860 prove they were perfect geometric shapes, they 00:07:01.860 --> 00:07:04.220 devised a brilliant method, which is detailed 00:07:04.220 --> 00:07:06.060 right there in the source text. So what did they 00:07:06.060 --> 00:07:09.019 do? They raised flags at regular intervals along 00:07:09.019 --> 00:07:11.540 the top of the embankments. Specifically, they 00:07:11.540 --> 00:07:14.160 set these stations exactly 300 feet apart. OK, 00:07:14.319 --> 00:07:16.360 300 feet apart. Then they placed their heavy 00:07:16.360 --> 00:07:18.680 surveyor's compass alternately at these stations, 00:07:19.339 --> 00:07:22.000 sighted down the line to the next flag, and calculated 00:07:22.000 --> 00:07:24.759 the bearings. OK, so if the structure was a true 00:07:24.759 --> 00:07:27.699 circle? Then the angles between these stations, 00:07:28.199 --> 00:07:30.600 measured every 300 feet along the entire circumference, 00:07:30.939 --> 00:07:33.420 would match perfectly. The mathematical progression 00:07:33.420 --> 00:07:36.259 of the angles would be flawless. The angles matched 00:07:36.259 --> 00:07:40.480 perfectly. Perfectly! Which is insane. Stop for 00:07:40.480 --> 00:07:42.139 a second and think about the implications of 00:07:42.139 --> 00:07:44.439 that for you listening. You can't just draw a 00:07:44.439 --> 00:07:47.870 circle. that is a mile in circumference by tying 00:07:47.870 --> 00:07:49.889 a rope to a center stake and walking around in 00:07:49.889 --> 00:07:52.269 a loop. No, a rope of that length would weigh 00:07:52.269 --> 00:07:54.810 an incredible amount. It would stretch. It would 00:07:54.810 --> 00:07:57.189 stretch. It would sag. It would snag on trees 00:07:57.189 --> 00:08:00.389 and boulders and brush. It's physically impossible 00:08:00.389 --> 00:08:03.209 to use a simple radius line for a structure of 00:08:03.209 --> 00:08:05.569 that magnitude. Absolutely impossible. To build 00:08:05.569 --> 00:08:08.649 a perfect circle on that scale requires an advanced 00:08:08.649 --> 00:08:12.089 understanding of geometry and a sophisticated 00:08:12.089 --> 00:08:15.529 method for keeping a consistent curve over vast 00:08:15.529 --> 00:08:18.889 distances without a central anchor point. But 00:08:18.889 --> 00:08:20.730 it wasn't just the circles that blew their minds. 00:08:20.829 --> 00:08:23.389 It was the squares. Oh, the squares are fascinating. 00:08:23.730 --> 00:08:26.509 Right. Through their strict standardization of 00:08:26.509 --> 00:08:29.370 measurement, Squire and Davis discovered mind 00:08:29.370 --> 00:08:32.669 blowing geometric consistency. They mapped multiple 00:08:32.669 --> 00:08:35.649 square enclosures separated by miles and miles 00:08:35.649 --> 00:08:37.769 of rugged terrain. Different river valleys, even. 00:08:37.809 --> 00:08:39.990 Yeah. And they found that these squares measured 00:08:39.990 --> 00:08:45.590 exactly 1080 feet on each side. 1080 feet, repeated 00:08:45.590 --> 00:08:48.409 flawlessly at entirely different sites. I mean 00:08:48.409 --> 00:08:51.899 the exactness of those 1080 foot squares. proves 00:08:51.899 --> 00:08:54.840 beyond a shadow of a doubt that the ancient builders 00:08:54.840 --> 00:08:56.759 possessed a standard of measurement. They had 00:08:56.759 --> 00:08:59.279 their own version of a meter or a yard. Right. 00:08:59.379 --> 00:09:01.259 And if they didn't have a written language that 00:09:01.259 --> 00:09:04.179 has survived, how are they communicating that 00:09:04.179 --> 00:09:07.159 exact standard unit of measurement across hundreds 00:09:07.159 --> 00:09:09.480 of miles? Well, that's the genius of the architecture. 00:09:09.759 --> 00:09:12.259 The structure itself is the record. Wow. And 00:09:12.259 --> 00:09:14.779 laying out a square that is 1 ,080 feet on a 00:09:14.779 --> 00:09:17.259 side requires 90 degree angles that are absolutely 00:09:17.259 --> 00:09:20.059 true. Because if you're off by even a tiny bit, 00:09:20.059 --> 00:09:22.350 if you are off even half a degree on your first 00:09:22.350 --> 00:09:24.470 corner, by the time you try to close that square 00:09:24.470 --> 00:09:26.629 nearly a mile later, your walls will miss each 00:09:26.629 --> 00:09:29.139 other entirely. They just won't line up. Exactly. 00:09:29.419 --> 00:09:31.919 They had the means to determine precise angles 00:09:31.919 --> 00:09:34.679 without the modern magnetic compasses that Squire 00:09:34.679 --> 00:09:37.179 and Davis were using. So Squire and Davis are 00:09:37.179 --> 00:09:39.240 tromping through the mud, dragging their metal 00:09:39.240 --> 00:09:42.080 chains, plotting these incredibly precise angles. 00:09:42.580 --> 00:09:45.340 And as they accumulate all this data, their measurements 00:09:45.340 --> 00:09:47.519 quickly reveal that the earthworks were divided 00:09:47.519 --> 00:09:50.879 into two distinct categories based entirely on 00:09:50.879 --> 00:09:53.289 their design. because the architecture dictates 00:09:53.289 --> 00:09:56.730 the purpose. As they mapped, a really clear pattern 00:09:56.730 --> 00:09:59.389 emerged in the landscape. The first category 00:09:59.389 --> 00:10:01.990 they identified were the defensive works, the 00:10:01.990 --> 00:10:04.549 fortresses. And the way they deduced this is 00:10:04.549 --> 00:10:06.490 really a master class in reading topography. 00:10:06.679 --> 00:10:09.159 because defensive works were always located on 00:10:09.159 --> 00:10:11.480 naturally strong, easily defended positions. 00:10:11.679 --> 00:10:13.980 Right, we are talking about the tops of steep 00:10:13.980 --> 00:10:16.960 bluffs, or peninsulas formed by the sharp bends 00:10:16.960 --> 00:10:19.559 of rivers where nature has already provided a 00:10:19.559 --> 00:10:22.039 wall on three sides. Topography was the first 00:10:22.039 --> 00:10:24.610 clue. But the engineering itself confirmed it, 00:10:24.950 --> 00:10:26.889 because in these defensive works, the ditch, 00:10:26.970 --> 00:10:29.210 the Foss, was almost always on the outside of 00:10:29.210 --> 00:10:31.169 the wall. Which is exactly what you see in medieval 00:10:31.169 --> 00:10:33.730 European castles or modern military bunkers. 00:10:34.029 --> 00:10:36.250 You want the enemy to have to climb down into 00:10:36.250 --> 00:10:39.269 a trench, right? And then scale the steepest 00:10:39.269 --> 00:10:41.830 part of the wall while you were firing down at 00:10:41.830 --> 00:10:44.590 them from above. Exactly. And they also documented 00:10:44.590 --> 00:10:47.909 complex overlapping gateways. Instead of just 00:10:47.909 --> 00:10:50.490 leaving a gap in the wall for a door, the ancient 00:10:50.490 --> 00:10:53.330 engineers would overlap the walls, creating a 00:10:53.330 --> 00:10:56.190 narrow winding corridor. So attackers would have 00:10:56.190 --> 00:10:58.169 to funnel through this maze. Funnel through, 00:10:58.450 --> 00:11:01.049 slowing them down and exposing their unprotected 00:11:01.049 --> 00:11:03.149 flanks to the defenders standing on top of the 00:11:03.149 --> 00:11:05.490 walls. The text actually highlights the fortified 00:11:05.490 --> 00:11:07.690 hill in Butler County, where Squire and Davis 00:11:07.690 --> 00:11:10.909 even found stone pavements and earthen lines 00:11:10.909 --> 00:11:13.389 specifically built to cover the entrances. Yeah, 00:11:13.389 --> 00:11:16.330 it was serious life or death military engineering. 00:11:16.429 --> 00:11:18.529 But here's where it gets really interesting. 00:11:19.090 --> 00:11:20.909 When you look at the second category of earthworks, 00:11:21.029 --> 00:11:25.029 the symmetrical works, the contrast is absolutely 00:11:25.029 --> 00:11:27.529 stark. Night and day. If the defensive works 00:11:27.529 --> 00:11:30.049 are like military bunkers built for survival, 00:11:30.629 --> 00:11:32.570 the symmetrical works are like grand cathedrals. 00:11:32.750 --> 00:11:34.809 Yeah, the sacred works were almost never built 00:11:34.809 --> 00:11:36.909 on high defensible ground. No, they were down 00:11:36.909 --> 00:11:39.870 on the broad, flat, fertile river terraces. And 00:11:39.870 --> 00:11:42.789 instead of following the irregular, jagged contours 00:11:42.789 --> 00:11:45.470 of a hilltop, They were characterized by that 00:11:45.470 --> 00:11:47.970 perfect geometry we just talked about. The exact 00:11:47.970 --> 00:11:51.230 squares, the perfect circles, and the massive 00:11:51.230 --> 00:11:54.149 octagons. And here is the mechanical clincher 00:11:54.149 --> 00:11:57.230 that proves they weren't forts. In these symmetrical 00:11:57.230 --> 00:12:00.250 works, the ditch is almost always on the inside 00:12:00.250 --> 00:12:02.450 of the wall. Which is completely useless for 00:12:02.450 --> 00:12:05.269 defense. Totally useless. If you are defending 00:12:05.269 --> 00:12:07.990 a wall from an invading force and the trench 00:12:07.990 --> 00:12:10.580 is behind you on the inside, You have nowhere 00:12:10.580 --> 00:12:13.679 to retreat. Right. The enemy has a clear, flat 00:12:13.679 --> 00:12:15.779 run at the outside of your wall, and if they 00:12:15.779 --> 00:12:17.960 breach it, you are trapped in your own ditch. 00:12:18.120 --> 00:12:20.740 It's a death trap. So the interior ditch proves 00:12:20.740 --> 00:12:23.340 these structures had a different likely religious 00:12:23.340 --> 00:12:26.259 or civic purpose. It was perhaps meant to separate 00:12:26.259 --> 00:12:28.840 sacred ground from the mundane world rather than 00:12:28.840 --> 00:12:31.620 to repel an army. The ultimate example of this 00:12:31.620 --> 00:12:34.019 civic architecture has to be the Newark Works 00:12:34.019 --> 00:12:36.509 in Ohio. According to the source material, this 00:12:36.509 --> 00:12:39.029 single complex covered an area of two miles square. 00:12:39.330 --> 00:12:42.450 It's massive. It featured a huge octagon connected 00:12:42.450 --> 00:12:44.889 to a perfect circle by parallel walls that formed 00:12:44.889 --> 00:12:48.129 these broad, sweeping avenues. And presiding 00:12:48.129 --> 00:12:51.929 over it all was the observatory mound, this massive 00:12:51.929 --> 00:12:55.529 elevation that overlooks the entire Newark complex. 00:12:55.830 --> 00:12:57.730 When you look at the Newark works, you are looking 00:12:57.730 --> 00:13:01.129 at pattern recognition at a societal scale. The 00:13:01.129 --> 00:13:03.070 ancient builders weren't just throwing up dirt 00:13:03.070 --> 00:13:05.470 randomly. They had a plan. They had a highly 00:13:05.470 --> 00:13:08.570 organized society with dedicated military engineering 00:13:08.570 --> 00:13:12.149 for times of war and dedicated civic or religious 00:13:12.149 --> 00:13:15.269 architecture for times of peace. That level of 00:13:15.269 --> 00:13:19.110 societal organization totally shatters the 19th 00:13:19.110 --> 00:13:22.009 century prejudice that these were just primitive 00:13:22.009 --> 00:13:24.830 wandering hunter -gatherers. Absolutely shatters 00:13:24.830 --> 00:13:26.909 it. But mapping the surface, you know, tracing 00:13:26.909 --> 00:13:28.769 those walls with a compass that was only half 00:13:28.769 --> 00:13:31.299 the job. Right, because to truly understand the 00:13:31.299 --> 00:13:34.340 scientific accuracy of Squire and Davis, we have 00:13:34.340 --> 00:13:36.460 to look at how they investigated the inside of 00:13:36.460 --> 00:13:38.220 the earthworks. They had to get their hands dirty. 00:13:38.559 --> 00:13:40.460 They had to invent a way to look underground 00:13:40.460 --> 00:13:43.000 without destroying the very thing they were studying. 00:13:43.200 --> 00:13:46.019 And the transition from surface surveying to 00:13:46.019 --> 00:13:48.659 excavation is where their methodology truly shines. 00:13:49.320 --> 00:13:51.779 Because before Squire and Davis, excavating a 00:13:51.779 --> 00:13:54.039 mound usually meant some treasure hunter with 00:13:54.039 --> 00:13:56.480 a shovel hacking recklessly into the side of 00:13:56.480 --> 00:13:59.360 a hill until they found a shiny rock or a bone. 00:13:59.519 --> 00:14:01.840 Completely ruining the structural integrity of 00:14:01.840 --> 00:14:04.340 the process. Destroying all the context, yeah. 00:14:04.860 --> 00:14:07.960 But Squire and Davis applied strict engineering 00:14:07.960 --> 00:14:10.379 principles to their excavations. They didn't 00:14:10.379 --> 00:14:13.899 just dig a haphazard hole. No. They sink precise 00:14:13.899 --> 00:14:17.240 vertical shafts, typically five to nine feet 00:14:17.240 --> 00:14:19.340 square. Directly from the apex, the very top 00:14:19.340 --> 00:14:21.519 of the mounds, straight down to the original 00:14:21.519 --> 00:14:23.649 ground level. And if they needed to explore the 00:14:23.649 --> 00:14:25.830 base further, they would push horizontal drifts 00:14:25.830 --> 00:14:28.470 or tunnels outward from the bottom of that central 00:14:28.470 --> 00:14:31.190 shaft. And as they dug these vertical shafts, 00:14:31.470 --> 00:14:33.750 they didn't just shovel dirt into a pile and 00:14:33.750 --> 00:14:36.169 ignore it. They actively read the dolt. They 00:14:36.169 --> 00:14:38.909 recorded the stratigraphy. Yes. The text details 00:14:38.909 --> 00:14:41.190 how they meticulously mapped the layers of the 00:14:41.190 --> 00:14:43.730 mound as they descended. They noted alternating 00:14:43.730 --> 00:14:47.169 convex layers of earth, thin strata of sand and 00:14:47.169 --> 00:14:49.230 layers of gravel. Okay, let's talk about the 00:14:49.230 --> 00:14:52.029 mechanics of those layers. Because some skeptics 00:14:52.029 --> 00:14:54.850 at the time still argued that these mounds might 00:14:54.850 --> 00:14:57.549 just be natural formations, you know, left behind 00:14:57.549 --> 00:15:01.009 by ancient floods or retreating glaciers. But 00:15:01.009 --> 00:15:03.529 Squire and Davis pointed out a fundamental rule 00:15:03.529 --> 00:15:07.309 of geology. Water deposits material in flat, 00:15:07.470 --> 00:15:10.470 horizontal layers as it settles. Right. But the 00:15:10.470 --> 00:15:12.950 layers inside the mounds were perfectly convex. 00:15:13.110 --> 00:15:15.549 They curved over the center, forming a dome shape. 00:15:15.789 --> 00:15:18.990 You only get that specific stratigraphy if human 00:15:18.990 --> 00:15:21.110 beings are walking up a ramp and systematically 00:15:21.110 --> 00:15:23.870 dumping baskets of earth, sand and gravel layer 00:15:23.870 --> 00:15:26.529 upon layer over a central point. Exactly. It 00:15:26.529 --> 00:15:29.769 was an airtight, empirical argument for artificial 00:15:29.769 --> 00:15:32.570 origin. But the stratigraphy solved an even bigger 00:15:32.570 --> 00:15:34.250 problem for them. I want you to picture this. 00:15:34.879 --> 00:15:37.740 You are digging in a mound and you find a skeleton, 00:15:37.899 --> 00:15:40.899 and next to it is a metal button from the 1700s. 00:15:40.919 --> 00:15:43.279 Uh -oh. Right? Does that mean the mound was built 00:15:43.279 --> 00:15:45.919 in the 1700s? How do you know that artifact isn't 00:15:45.919 --> 00:15:47.720 from someone who just dug a hole and dropped 00:15:47.720 --> 00:15:50.039 it there centuries after the mound was actually 00:15:50.039 --> 00:15:52.360 built? Temporal contamination is the absolute 00:15:52.360 --> 00:15:55.299 nightmare of every archaeologist. It really is. 00:15:55.580 --> 00:15:58.600 Squire and Davis solved it by using the continuity 00:15:58.600 --> 00:16:02.019 of those thin, convex sand layers to determine 00:16:02.019 --> 00:16:04.710 if a mound had been disturbed. Because over the 00:16:04.710 --> 00:16:07.549 centuries later, Native American tribes would 00:16:07.549 --> 00:16:10.629 often bury their dead in the upper portions of 00:16:10.629 --> 00:16:13.169 these ancient mounds. It makes total sense. You 00:16:13.169 --> 00:16:16.009 find a pre -existing dry hill that stands above 00:16:16.009 --> 00:16:17.929 the floodplain and you think, well, that's a 00:16:17.929 --> 00:16:19.950 great place for a grave. Without necessarily 00:16:19.950 --> 00:16:22.169 knowing who built the hill a thousand years earlier. 00:16:22.529 --> 00:16:25.370 Precisely. And when those later tribes dug their 00:16:25.370 --> 00:16:28.169 graves, they would inevitably break through those 00:16:28.169 --> 00:16:30.980 upper layers of sand. Squire and Davis noted 00:16:30.980 --> 00:16:33.519 that if the strata were broken, the burials were 00:16:33.519 --> 00:16:36.340 recent. I like to compare those undisturbed sand 00:16:36.340 --> 00:16:39.480 layers to an unbroken wax seal on a sealed letter. 00:16:39.600 --> 00:16:41.500 Oh, that's a great analogy. Right. Because if 00:16:41.500 --> 00:16:43.659 the wax seal is broken, you know someone has 00:16:43.659 --> 00:16:45.779 tampered with the contents. Yeah. But if you 00:16:45.779 --> 00:16:48.320 dig down and those incredibly thin sand layers 00:16:48.320 --> 00:16:51.440 are perfectly intact, completely unbroken all 00:16:51.440 --> 00:16:53.519 the way across the walls of your five by nine 00:16:53.519 --> 00:16:56.860 foot shaft, then you have absolute scientific 00:16:56.860 --> 00:16:58.929 certainty. You know that whatever is underneath 00:16:58.929 --> 00:17:01.570 that layer has been there since the very day 00:17:01.570 --> 00:17:03.950 the mound was built. By documenting the exact 00:17:03.950 --> 00:17:06.829 strata, they established a chronological timeline 00:17:06.829 --> 00:17:09.750 within a single structure. It allowed them to 00:17:09.750 --> 00:17:12.809 isolate the original undisturbed artifacts of 00:17:12.809 --> 00:17:15.569 the true mound builders at the base, completely 00:17:15.569 --> 00:17:17.950 separating them from centuries of historical 00:17:17.950 --> 00:17:20.289 mix -ups. So they follow these unbroken sand 00:17:20.289 --> 00:17:22.589 layers down, proving no one had disturbed the 00:17:22.589 --> 00:17:24.450 earth since it was built. But what were they 00:17:24.450 --> 00:17:26.609 actually protecting down there? That's the big 00:17:26.609 --> 00:17:28.369 question. When they hit the bottom of the mounds 00:17:28.369 --> 00:17:30.910 on the Scioto River, they didn't find graves. 00:17:31.490 --> 00:17:34.690 They found ash. They discovered the altars of 00:17:34.690 --> 00:17:38.069 fire. This is where Squire and Davis's excavations 00:17:38.069 --> 00:17:40.730 revealed a deeply complex religious and economic 00:17:40.730 --> 00:17:42.990 life. Let's focus on a site they named Mound 00:17:42.990 --> 00:17:46.130 City. It is a group of 26 mounds, all contained 00:17:46.130 --> 00:17:49.349 inside one massive earthwork enclosure. And when 00:17:49.349 --> 00:17:51.769 they sank their shafts down through the unbroken 00:17:51.769 --> 00:17:54.289 wax seals of these specific mounds, resting right 00:17:54.289 --> 00:17:56.529 on the original surface of the earth, they found 00:17:56.529 --> 00:18:00.029 symmetrical basins of fine clay. These clay basins 00:18:00.029 --> 00:18:03.470 were perfectly shaped, round, square, or oval. 00:18:03.690 --> 00:18:06.329 But what was truly remarkable was the thermal 00:18:06.329 --> 00:18:09.730 alteration. Yeah, explain that. These clay basins 00:18:09.730 --> 00:18:12.809 had been baked to extreme hardness by intense, 00:18:13.369 --> 00:18:16.230 continuous fire. The text specifies that the 00:18:16.230 --> 00:18:19.630 clay was burned up to 22 inches deep. 22 inches? 00:18:19.769 --> 00:18:22.250 Think about the physics of that. A regular campfire 00:18:22.250 --> 00:18:25.309 might bake the soil an inch or two. To bake solid 00:18:25.309 --> 00:18:28.450 clay almost two feet deep, requires a roaring 00:18:28.450 --> 00:18:31.490 inferno, sustained over an incredibly long period 00:18:31.490 --> 00:18:34.230 of time, and deposited directly into these altars, 00:18:34.269 --> 00:18:36.670 right into the fires, were incredible treasures. 00:18:36.809 --> 00:18:39.250 These were offerings. Everything placed in these 00:18:39.250 --> 00:18:41.369 basins had been subjected to the immense heat, 00:18:41.609 --> 00:18:43.849 often fracturing and shattering from the intensity. 00:18:44.029 --> 00:18:46.269 The text has amazing detailed descriptions of 00:18:46.269 --> 00:18:49.450 these artifacts. They found over 200 intricately 00:18:49.450 --> 00:18:52.869 carved porphyry pipes. And we really have to 00:18:52.869 --> 00:18:54.910 talk about porphyry. What is it exactly? It is 00:18:54.910 --> 00:18:57.690 an igneous rock, incredibly hard, much harder 00:18:57.690 --> 00:19:00.490 than marble or limestone, yet these pipes were 00:19:00.490 --> 00:19:03.190 sculpted into astonishingly accurate animal forms. 00:19:03.390 --> 00:19:07.109 Herons, frogs, beavers. The detail was so precise 00:19:07.109 --> 00:19:10.309 that zoologists could identify the exact species 00:19:10.309 --> 00:19:13.049 of the animal just by looking at the stone carving. 00:19:13.670 --> 00:19:17.509 Wow. But to carve porphyry with that level of 00:19:17.509 --> 00:19:20.309 anatomical precision? without hardened steel 00:19:20.309 --> 00:19:22.970 tools. I mean, that is a staggering technical 00:19:22.970 --> 00:19:26.049 achievement. That requires sand, water, and friction. 00:19:26.589 --> 00:19:30.349 Just slowly, slowly wearing away the stone over 00:19:30.349 --> 00:19:32.630 thousands of hours. It implies a society that 00:19:32.630 --> 00:19:34.990 has specialized artisans. Yeah. People whose 00:19:34.990 --> 00:19:37.569 entire job is to create these masterpieces. Which 00:19:37.569 --> 00:19:39.309 means someone else is growing the food to feed 00:19:39.309 --> 00:19:42.130 them. You have a divided labor force. And the 00:19:42.130 --> 00:19:44.670 treasures didn't stop at stone. They found copper 00:19:44.670 --> 00:19:47.250 axes and thick copper ornaments. And Squire and 00:19:47.250 --> 00:19:49.650 Davis noted the metallurgy here, which is fascinating. 00:19:50.049 --> 00:19:53.190 This copper was hammered cold from pure native 00:19:53.190 --> 00:19:55.430 copper. Which is a very specific metallurgical 00:19:55.430 --> 00:19:57.569 process, right? They didn't smelt the ore by 00:19:57.569 --> 00:19:59.490 melting it down into a liquid and casting it? 00:19:59.589 --> 00:20:02.750 No, they pounded it into shape. But cold hammering 00:20:02.750 --> 00:20:05.390 copper makes it brittle. It will eventually crack. 00:20:05.690 --> 00:20:07.950 So how do they do it? To shape an axe, you have 00:20:07.950 --> 00:20:10.430 to hammer it, then gently heat it, which is called 00:20:10.430 --> 00:20:12.750 annealing, to soften it, then hammer it again. 00:20:12.910 --> 00:20:15.609 Over and over. It shows a deep, practical understanding 00:20:15.609 --> 00:20:18.789 of the material properties of metal. They also 00:20:18.789 --> 00:20:22.990 found mica, this shiny, flaky mineral, cut into 00:20:22.990 --> 00:20:25.490 perfect geometric shapes and crescents. Thousands 00:20:25.490 --> 00:20:28.069 of pearl beads, too. But the thing that really 00:20:28.069 --> 00:20:32.049 made me stop and reread the page was this. In 00:20:32.049 --> 00:20:34.789 the ashes of these altars, they found obsidian. 00:20:35.459 --> 00:20:38.759 Volcanic glass. Volcanic glass shaped into spears 00:20:38.759 --> 00:20:42.059 and knives. Wait a minute. Volcanic glass in 00:20:42.059 --> 00:20:45.279 Ohio. This raises an important question. Where 00:20:45.279 --> 00:20:48.279 did it come from? Yeah. Because there are no 00:20:48.279 --> 00:20:51.430 volcanoes in Ohio. If we connect this to the 00:20:51.430 --> 00:20:53.809 bigger picture, we were looking at empirical 00:20:53.809 --> 00:20:56.630 evidence of a massive continent -spanning supply 00:20:56.630 --> 00:20:58.809 chain. Let's trace the map they built just from 00:20:58.809 --> 00:21:01.029 the contents of these altars. The native copper 00:21:01.029 --> 00:21:03.509 came from the shores of Lake Superior, hundreds 00:21:03.509 --> 00:21:05.569 of miles to the north. The mica came from the 00:21:05.569 --> 00:21:07.990 Allegheny Mountains to the east. The pearls and 00:21:07.990 --> 00:21:10.029 marine shells came from the Gulf of Mexico to 00:21:10.029 --> 00:21:12.509 the south. And the obsidian. That had to come 00:21:12.509 --> 00:21:14.750 from the distant west, either the Rocky Mountains 00:21:14.750 --> 00:21:17.980 or central Mexico. Just by scientifically logging 00:21:17.980 --> 00:21:21.359 the items in these fire pits, Squire and Davis 00:21:21.359 --> 00:21:24.740 mapped a trade network that would span thousands 00:21:24.740 --> 00:21:27.099 of miles. They didn't need to guess about whether 00:21:27.099 --> 00:21:29.319 these people were isolated. The empirical evidence 00:21:29.319 --> 00:21:31.599 proved they were tapping into resources across 00:21:31.599 --> 00:21:34.200 the entire continent. You don't have obsidian 00:21:34.200 --> 00:21:36.799 traveling from the Rockies to Ohio without well 00:21:36.799 --> 00:21:39.759 -established routes. Right. Diplomacy and an 00:21:39.759 --> 00:21:42.119 economy capable of supporting that kind of long 00:21:42.119 --> 00:21:45.269 -distance exchange. It is breathtaking. It completely 00:21:45.269 --> 00:21:48.049 rewrites the assumption of a sparsely populated, 00:21:48.210 --> 00:21:50.650 disconnected frontier. Absolutely. But while 00:21:50.650 --> 00:21:53.190 Mound City was defined by fire and sacrifice, 00:21:53.769 --> 00:21:56.809 Squire and Davis' systematic excavations revealed 00:21:56.809 --> 00:21:59.250 that other mounds served very different purposes, 00:21:59.829 --> 00:22:01.869 highlighting the vast diversity of the culture. 00:22:02.049 --> 00:22:04.809 Because not every mound was an altar, they identified 00:22:04.809 --> 00:22:07.859 a second major type. The sepulchral mounds. Cities 00:22:07.859 --> 00:22:10.200 of the dead. Exactly. These were distinct from 00:22:10.200 --> 00:22:13.079 the altar mounds. Instead of baked clay basins, 00:22:13.099 --> 00:22:15.140 they usually contained a single skeleton at the 00:22:15.140 --> 00:22:17.920 base, often encased in a complex timber or log 00:22:17.920 --> 00:22:20.000 vault. The standout example they highlight is 00:22:20.000 --> 00:22:22.940 the Grave Creek Mound in West Virginia. This 00:22:22.940 --> 00:22:26.599 thing was a monster 50 feet high. Massive. And 00:22:26.599 --> 00:22:28.859 instead of just sinking a vertical shaft, they 00:22:28.859 --> 00:22:31.940 mapped it using horizontal excavation, driving 00:22:31.940 --> 00:22:33.859 a drift straight into the side of the mound. 00:22:34.059 --> 00:22:37.059 And inside, they found distinct timber vaults 00:22:37.059 --> 00:22:40.380 containing skeletons. It was a massive labor 00:22:40.380 --> 00:22:42.940 -intensive monument dedicated entirely to the 00:22:42.940 --> 00:22:45.319 dead. And then there is a third category which 00:22:45.319 --> 00:22:47.779 represents a massive shift in architectural style, 00:22:48.220 --> 00:22:50.180 the temple mounds. These are mostly found in 00:22:50.180 --> 00:22:52.779 the south. Instead of the cone shapes we see 00:22:52.779 --> 00:22:56.220 in the Ohio Valley, these are massive, flat -topped, 00:22:56.279 --> 00:22:58.519 truncated pyramids. They're built with graded 00:22:58.519 --> 00:23:01.059 ascents, essentially giant earthen ramps and 00:23:01.059 --> 00:23:03.240 flat terraces. Likely serving as the foundations 00:23:03.240 --> 00:23:05.960 for massive wooden structures or temples. The 00:23:05.960 --> 00:23:08.200 absolute granddaddy of them all, which the text 00:23:08.200 --> 00:23:11.890 discusses, is Cahokia in Illinois. The source 00:23:11.890 --> 00:23:14.490 material notes that the main pyramid at Cahokia 00:23:14.490 --> 00:23:17.710 contains 20 million cubic feet of earth. It's 00:23:17.710 --> 00:23:19.569 hard to even picture that. I want to give you 00:23:19.569 --> 00:23:22.250 a true sense of scale for that number. A standard 00:23:22.250 --> 00:23:24.750 modern dump truck holds about 400 cubic feet 00:23:24.750 --> 00:23:28.069 of dirt. To move 20 million cubic feet, you would 00:23:28.069 --> 00:23:32.119 need 50 ,000 modern dump trucks. and they did 00:23:32.119 --> 00:23:35.759 it by hand exactly dug with stone or shell tools 00:23:35.759 --> 00:23:38.680 carried in woven baskets that held maybe 50 pounds 00:23:38.680 --> 00:23:41.400 at a time dumped and then stamped down basket 00:23:41.400 --> 00:23:45.200 by basket 50 000 dump trucks worth of soil that 00:23:45.200 --> 00:23:47.279 is the equivalent of building the great pyramid 00:23:47.279 --> 00:23:50.440 of giza but doing it entirely with dirt it is 00:23:50.440 --> 00:23:53.180 a staggering logistical feat And it implies something 00:23:53.180 --> 00:23:55.500 fundamental about the mechanics of their society. 00:23:55.700 --> 00:23:58.420 What's that? You cannot feed an army of earthmovers 00:23:58.420 --> 00:24:01.099 year after year by just hunting deer and gathering 00:24:01.099 --> 00:24:03.039 berries. Oh, you would exhaust the local game 00:24:03.039 --> 00:24:05.529 in a month. Right. These massive civic works 00:24:05.529 --> 00:24:08.349 imply an incredibly dense, highly organized, 00:24:08.490 --> 00:24:11.069 and deeply agricultural population. You need 00:24:11.069 --> 00:24:14.230 massive, sustained agricultural surplus, vast 00:24:14.230 --> 00:24:16.710 fields of corn, just to free up the thousands 00:24:16.710 --> 00:24:19.490 of laborers required to build Cahokia. The scale 00:24:19.490 --> 00:24:21.789 of the architecture proves the scale of the agriculture. 00:24:22.029 --> 00:24:24.069 So we have the altars of fire, the sepulchers 00:24:24.069 --> 00:24:27.190 of the dead, the massive temple pyramids. But 00:24:27.190 --> 00:24:29.869 perhaps the strangest earthworks of all are found 00:24:29.869 --> 00:24:32.269 in the Northwest, specifically in Wisconsin. 00:24:32.460 --> 00:24:35.799 The animal effigies. Yes. Relying on surveys 00:24:35.799 --> 00:24:38.279 conducted by R .C. Taylor and Professor Locke, 00:24:38.440 --> 00:24:41.240 Squire and Davis include detailed accounts of 00:24:41.240 --> 00:24:45.119 mounds shaped like gigantic animals. Bears, foxes, 00:24:45.359 --> 00:24:48.319 birds, some of them stretching over 150 feet 00:24:48.319 --> 00:24:50.799 long, molded perfectly out of the prairie soil. 00:24:50.920 --> 00:24:52.660 And what I love is how Professor Locke approached 00:24:52.660 --> 00:24:55.119 them. He didn't just sketch a rough picture and 00:24:55.119 --> 00:24:57.859 say, well, it looks like a fox. No. He applied 00:24:57.859 --> 00:25:00.839 that exact same rigorous scientific approach 00:25:00.839 --> 00:25:03.920 that Squire and Davis demanded. He recorded exact 00:25:03.920 --> 00:25:06.680 anatomical measurements of the earthworks. He 00:25:06.680 --> 00:25:08.839 would measure the distance from the, quote, eye 00:25:08.839 --> 00:25:11.059 to the shoulder, end quote, and from the shoulder 00:25:11.059 --> 00:25:13.549 to the foot of the earthen animal. He was capturing 00:25:13.549 --> 00:25:16.450 their exact proportions to prove they were intentional, 00:25:16.450 --> 00:25:19.549 scaled representations of wildlife, not just 00:25:19.549 --> 00:25:22.049 random lumps of soil. It is a perfect example 00:25:22.049 --> 00:25:24.569 of keeping the scientific methodology consistent, 00:25:25.009 --> 00:25:27.069 even when the subject matter changes from the 00:25:27.069 --> 00:25:29.990 pure geometry of the Ohio squares to the animal 00:25:29.990 --> 00:25:31.930 effigies of Wisconsin. It's all about the data. 00:25:32.210 --> 00:25:33.970 So let's step back and look at what they have 00:25:33.970 --> 00:25:36.869 accomplished so far. Through their meticulous 00:25:36.869 --> 00:25:39.759 surveying, we know what they built. We know how 00:25:39.759 --> 00:25:42.500 they built it, moving tens of millions of cubic 00:25:42.500 --> 00:25:44.720 feet of dirt. We know they traded across the 00:25:44.720 --> 00:25:48.339 entire continent. Right. But one massive scientific 00:25:48.339 --> 00:25:51.000 question remained for the authors, the biggest 00:25:51.000 --> 00:25:54.819 mystery of all. When were they built? How old 00:25:54.819 --> 00:25:57.970 is this civilization? This is perhaps their most 00:25:57.970 --> 00:25:59.970 elegant deduction, because we have to remember 00:25:59.970 --> 00:26:03.990 this was 1848. Right. Radiocarbon dating, which 00:26:03.990 --> 00:26:06.730 modern archaeologists use to date organic material, 00:26:07.089 --> 00:26:08.930 wouldn't be invented for another century. So 00:26:08.930 --> 00:26:11.289 what does this all mean? Without carbon dating, 00:26:11.490 --> 00:26:14.630 without a written calendar left behind, how did 00:26:14.630 --> 00:26:17.369 Squire and Davis scientifically calculate the 00:26:17.369 --> 00:26:20.430 age of the earthworks without resorting to guesswork? 00:26:20.750 --> 00:26:22.980 They turned to the natural world. First, they 00:26:22.980 --> 00:26:25.759 used botany as a biological clock. OK, how did 00:26:25.759 --> 00:26:28.140 that work? Well, when the first European settlers 00:26:28.140 --> 00:26:31.019 arrived in these valleys, these massive mounds 00:26:31.019 --> 00:26:33.660 and geometric enclosures were already completely 00:26:33.660 --> 00:26:36.319 covered by primitive old -growth forests. They 00:26:36.319 --> 00:26:38.839 weren't bare earth. No, they looked like natural 00:26:38.839 --> 00:26:42.140 hills covered in huge trees. Squire and Davis 00:26:42.140 --> 00:26:44.759 literally cut down the mass of trees growing 00:26:44.759 --> 00:26:47.759 directly on top of the earthwork walls and counted 00:26:47.759 --> 00:26:50.599 the annual rings. And they found trees that were 00:26:50.599 --> 00:26:54.039 600 to 800 years old, just growing right out 00:26:54.039 --> 00:26:56.109 of the top of the embankments. But that was only 00:26:56.109 --> 00:26:58.970 the minimum age. Why? Because they also noted 00:26:58.970 --> 00:27:01.650 that these 800 -year -old trees were often growing 00:27:01.650 --> 00:27:04.609 out of the decayed, crumbling remains of equally 00:27:04.609 --> 00:27:06.730 massive predecessors. Think about the timeline 00:27:06.730 --> 00:27:09.210 that requires. After the mounds were finally 00:27:09.210 --> 00:27:12.869 abandoned, seeds took root. A forest grew, lived 00:27:12.869 --> 00:27:15.630 its entire lifespan of many centuries, died, 00:27:15.890 --> 00:27:18.339 decayed into rich soil. And then another old 00:27:18.339 --> 00:27:20.500 growth forest grew on top of those remains. And 00:27:20.500 --> 00:27:22.740 lived for 800 years before Squire and Davis came 00:27:22.740 --> 00:27:25.099 along with an axe to count the rings. Exactly. 00:27:25.279 --> 00:27:27.500 That pushes the timeline back incredibly far. 00:27:27.599 --> 00:27:29.500 But the botany was just the warm -up. Yeah. The 00:27:29.500 --> 00:27:31.319 most brilliant deduction they made, the one that 00:27:31.319 --> 00:27:33.619 truly cemented the antiquity of the mounds, was 00:27:33.619 --> 00:27:36.220 based on geology. specifically the formation 00:27:36.220 --> 00:27:38.579 of the river terraces. I love this part because 00:27:38.579 --> 00:27:41.460 it is so incredibly logical once you see it. 00:27:42.019 --> 00:27:44.200 The rivers in the Mississippi and Ohio valleys 00:27:44.200 --> 00:27:47.339 have slowly cut down through the earth over millennia. 00:27:47.660 --> 00:27:50.200 Right. As a river cuts deeper into the bedrock, 00:27:50.380 --> 00:27:53.420 it leaves its old floodplains behind as distinct 00:27:53.420 --> 00:27:56.460 step -like terraces on the sides of the valley. 00:27:56.619 --> 00:27:59.710 Like giant stairs. Yes. The highest terrace is 00:27:59.710 --> 00:28:02.130 the oldest. That's where the river flowed tens 00:28:02.130 --> 00:28:05.049 of thousands of years ago. As you walk down the 00:28:05.049 --> 00:28:07.569 steps toward the water, the terraces get younger. 00:28:07.849 --> 00:28:10.170 The lowest terrace, the one right next to the 00:28:10.170 --> 00:28:12.769 modern river, is the newest floodplain formed 00:28:12.769 --> 00:28:16.069 most recently. So Squire and Davis mapped thousands 00:28:16.069 --> 00:28:18.549 of these earthworks across multiple river valleys. 00:28:18.769 --> 00:28:20.950 They found them heavily concentrated on the second 00:28:20.950 --> 00:28:23.009 terrace. They found them on the third terrace. 00:28:23.049 --> 00:28:25.730 They found them on the fourth, the highest terraces. 00:28:25.809 --> 00:28:28.269 But as they looked at their exhaustive data, 00:28:28.650 --> 00:28:32.650 they noted a complete 100 % absence of any works 00:28:32.650 --> 00:28:35.710 on the first terrace, the lowest and latest formed 00:28:35.710 --> 00:28:38.569 floodplain. And that is the geological smoking 00:28:38.569 --> 00:28:41.130 gun. Why does that matter so much? Because human 00:28:41.130 --> 00:28:43.609 civilizations, especially agricultural ones that 00:28:43.609 --> 00:28:46.829 rely on river transport, always build near the 00:28:46.829 --> 00:28:49.069 water. You want to be close to the river. Exactly. 00:28:49.430 --> 00:28:51.849 The first terrace has the most fertile soil and 00:28:51.849 --> 00:28:54.690 the easiest access to the river. So if that lowest 00:28:54.690 --> 00:28:57.150 terrace had existed when the mound builders were 00:28:57.150 --> 00:28:59.269 alive, they absolutely would have built their 00:28:59.269 --> 00:29:01.630 cities and enclosures on it. They wouldn't have 00:29:01.630 --> 00:29:04.220 ignored the best land. The fact that there isn't 00:29:04.220 --> 00:29:07.259 a single earthwork on the first terrace scientifically 00:29:07.259 --> 00:29:10.559 proves that the ancient civilization flourished, 00:29:10.980 --> 00:29:13.480 built their massive cities, and completely vanished 00:29:13.480 --> 00:29:16.119 before the river had even finished forming its 00:29:16.119 --> 00:29:19.519 current lowest floodplain. It is an airtight 00:29:19.519 --> 00:29:22.190 empirical argument. They didn't need to invent 00:29:22.190 --> 00:29:24.869 a myth about wandering tribes or ancient giants. 00:29:25.410 --> 00:29:28.089 They used the earth itself to date the earthworks. 00:29:28.289 --> 00:29:31.289 The river carving down, step by step, century 00:29:31.289 --> 00:29:34.230 by century, acted as a geological clock. And 00:29:34.230 --> 00:29:36.009 the earthworks are just stranded up there on 00:29:36.009 --> 00:29:38.390 the upper steps of time, waiting for someone 00:29:38.390 --> 00:29:40.690 with a surveyor's compass to finally read the 00:29:40.690 --> 00:29:43.769 landscape correctly. It is just brilliant deduction. 00:29:44.289 --> 00:29:46.710 It really is. And it brings us to the end of 00:29:46.710 --> 00:29:48.819 our journey for today. We have traveled with 00:29:48.819 --> 00:29:50.940 you from the strict, truth -seeking mandates 00:29:50.940 --> 00:29:53.579 of the young Smithsonian Institution through 00:29:53.579 --> 00:29:56.579 the muddy, mosquito -filled forests where Squire 00:29:56.579 --> 00:29:59.940 and Davis dragged heavy chains to prove the existence 00:29:59.940 --> 00:30:03.420 of giant, perfect octagons. We descended down 00:30:03.420 --> 00:30:06.220 the square vertical shafts into the altars of 00:30:06.220 --> 00:30:08.599 fire, examining the mechanics of cold -hammered 00:30:08.599 --> 00:30:11.500 copper and tracing trade routes to the Rockies 00:30:11.500 --> 00:30:14.599 through pieces of obsidian. And finally, we climbed 00:30:14.599 --> 00:30:17.099 up the geological terraces of time to see how 00:30:17.099 --> 00:30:19.720 rivers and tree rings proved the immense antiquity 00:30:19.720 --> 00:30:22.160 of it all. Squire and Davis didn't just uncover 00:30:22.160 --> 00:30:24.859 artifacts. They brought the scientific method 00:30:24.859 --> 00:30:27.619 to the American frontier. They laid the bedrock 00:30:27.619 --> 00:30:30.359 for all of scientific archaeology in this hemisphere. 00:30:30.539 --> 00:30:33.079 They taught a young nation how to look, how to 00:30:33.079 --> 00:30:35.640 measure, and how to deduce truth from the soil 00:30:35.640 --> 00:30:38.359 without ever letting romantic imagination compromise 00:30:38.359 --> 00:30:41.519 the hard facts. And that leaves us with a final 00:30:41.519 --> 00:30:44.240 lingering thought for you to take away. If a 00:30:44.240 --> 00:30:47.079 civilization so vast and powerful, capable of 00:30:47.079 --> 00:30:49.119 moving tens of millions of cubic feet of earth 00:30:49.119 --> 00:30:52.019 by hand, capable of engineering perfect geometry 00:30:52.019 --> 00:30:54.500 on a massive scale and maintaining supply chains 00:30:54.500 --> 00:30:56.720 from the Rocky Mountains to the Gulf of Mexico. 00:30:56.859 --> 00:30:58.799 If they could vanish so completely that their 00:30:58.799 --> 00:31:02.160 actual names are lost to time, leaving only silent 00:31:02.160 --> 00:31:04.859 geometry beneath ancient trees. What monuments 00:31:04.859 --> 00:31:07.140 are we currently building on our own latest terrace 00:31:07.140 --> 00:31:09.559 that will puzzle the scientific surveyors of 00:31:09.559 --> 00:31:12.019 a distant unknown future? We are sitting here 00:31:12.019 --> 00:31:14.660 today in our modern world, confidently categorizing 00:31:14.660 --> 00:31:17.809 our reality, but someday Our cities might just 00:31:17.809 --> 00:31:20.509 be the murky, mysterious earthworks for someone 00:31:20.509 --> 00:31:23.069 else's surveyor compass. Thank you so much for 00:31:23.069 --> 00:31:24.869 joining us on this deep dive into the source 00:31:24.869 --> 00:31:26.589 material. We will see you next time.