ILLINOIS.
(Map [26].)
1. Alton, Madison County.—In the U. S. National Museum are four teeth of an undetermined species of Bison found somewhere in the vicinity of Alton. They are part of a collection made many years ago by Mr. William McAdams, and afterwards passed into the hands of Professor O. C. Marsh, then vertebrate palæontologist of the U. S. Geological Survey. It now belongs to the U. S. National Museum. Nearly all of these fossils were originally inclosed, wholly or partially, in nodules of fine sand, cemented together with carbonate of calcium. Where the teeth are exposed to view they are shown in a beautifully white condition; but the remaining matrix is so hard and adheres so strongly that it is practically impossible to remove it without greatly damaging the teeth. A list of the species found at Alton will be given on page [339]; also a discussion of their geologic age.
The bison teeth consist of four upper molars and the hinder half or more of the left hindermost molar. They were described by the writer (Proc. U. S. Nat. Mus., vol. LVIII, p. 115). They are somewhat larger than any belonging to the existing buffalo measured. They are larger, too, than those of the commonest extinct species, B. occidentalis. It is impossible to say at present to which extinct species they belonged. One naturally thinks of Bison latifrons, the bearer of the immense horns, but teeth have not yet been found associated with the horn-cores of that species.