308 GEOLOGY OF ILLINOIS. 



or more in diameter is met with in the beds of the ravines, but they are 

 not common. In the vicinity of Springfield this division of the Quatern- 

 ary ranges from twenty to forty feet in thickness, and this is probably 

 not far from, its average thickness throughout the county; but at some 

 localities there is a blue clay or hard pan below the brown clays, which 

 attains about the same thickness as the former, making the aggregate 

 thickness of the drift, where fully developed, from fifty to eighty feet. 

 No fossils have as yet been obtained from the drift in this county, so 

 far as I am aware, though the tooth of a mammoth was found some 

 years ago in the bluffs of the Sangamon, and near the surface, and 

 probably came from beds not older than the loess. 



The discovery of the Niantic mastodon, some three years since, 

 between Illiopolis and Niantic, and just over the Macon county line, 

 excited considerable interest when the discovery was first announced, 

 and I visited the locality, and was present when a part of the bones 

 were taken out. The discovery was made on the farm of Wm. F. Cor- 

 rell, in sinking a stock well, in a wet, spongy piece of ground, located 

 in a swale or depression of the surface, that had evidently once been a 

 pond of water,- and had been filled up by the wash from the surround- 

 ing highland, until it formed a morass, or quagmire, in dry weather. 

 TLe bones were about four feet below the surface, and partly imbedded 

 in a light-gray quicksand filled with fresh water shells, Planorlis, Cy- 

 clasj Physa, etc. Above this quicksand there was four feet of black, 

 peaty soil, so soft that a common fence rail could be easily pushed 

 down through it. The quicksand had evidently once formed the bot- 

 tom of a fresh water pond, fed probably by springs, and was the resort 

 of the animals whose bones were found here. The first bone met with 

 in sinking the well was one of the tusks, and supposing it to be a small 

 tree, it was cut in two with an ax before its true character was sus- 

 pected. The other tusk was taken out whole, and measured nine feet in 

 length around the curve, and about two feet in circumference where it 

 was inserted in the skull. The lower jaw, with the teeth in place, and the 

 teeth of the upper jaw, and some of the smaller bones, were also found 

 in a good state of preservation. A fine pair of antlers of the elk, with 

 some other bones of the same animal, and bones of the buffalo and 

 deer, were found in the same position as the bones of the mastodon, 

 but the bones of the smaller animals, although imbedded at the same 

 depth, were lighter colored, less decayed, and appeared to have been 

 buried at a more recent period. The depth of the quicksand was not 

 fully ascertained, but it was probed to the depth of two feet or more 

 without reaching a solid bottom. 



