150 LESSONS FKOM NATUKE. [CHAP. VI. 



existence of a very ancient ami far-spread higher culture, of 

 which they now constitute the only traces in the spots where 

 they are found. 



Again he observes : 



&quot; The whole of North America, from the Gulf of Mexico to Canada, 

 is full of ancient works of earth and stone, chiefly found in the form 

 of mounds and embankments. They exist in countless thousands, and 

 I believe in every State ; but the most remarkable are in the great 

 plain or valley between the Alleghanies and the Eocky Mountains, a 

 district at least a thousand miles square. Some lines of embankment 

 are thirty feet high. Many areas inclosed by them are from one to two 

 hundred acres ; some are double this size. One group of works con 

 tains twenty miles of embankment. One of the mounds is one thousand 

 feet in circumference, and seventy feet high. Another is two thousand 

 feet round the base, and ninety feet high ; a truncated pyramid, with a 

 flat top of several acres. Many of the inclosures are in the form of 

 circles and squares, and in many cases these figures are mathematically 

 exact, notwithstanding their great size. In one of these exact squares 

 each side is a thousand and eighty feet long, and the area inclosed 

 twenty-seven acres. In one of the exact circles the diameter is seven 

 teen hundred feet, the area forty acres. The precision of these figures 

 has been ascertained by mathematical survey. The ellipse, also exact, 

 is found in other cases.&quot; 



Now, as he truly says : 



&quot; Neither a true circle, with a radius of eight hundred and fifty feet, 

 nor a true square, with a side of one thousand and eighty feet, can be 

 drawn upon open ground by any one without the help of exact 

 measures and mathematical knowledge.&quot; 



He proceeds : 



&quot; A numerous people spread over a wide empire must have had easy 

 means of internal communication. We see, accordingly, from the 

 objects found in the mounds, that they possessed copper in abundance, 

 which came, doubtless, from the shores of Lake Superior, where the 

 ancient mines have been rediscovered; obsidian, which is not found 

 nearer than Mexico ; mica, probably from South Carolina ; pearls, and 

 marine shells. And among the sculptured objects from Ohio are exact 

 representations of the Toucan, which belongs to tropical South America, 

 and the Manatee, found on the coast of Florida. 

 ~ &quot; The objects of the greatest interest are the sculptured stone tobacco 

 pipes; the oldest known tobacco pipes in the world, most of which 

 were found in the same mound in Ohio. 



&quot; These pipes are unique in form, and are carved out of hard 



