220 KANSAS CITY REVIEW OF SCIENCE, 
"The last great convulsion of nature, under the guidance of an all wise Prov- 
dence, ended the geological epoch and finished the earth, leaving it in its present 
outward form, which is called by geologists the quaternary or drift period. During 
this period the earth, from some cause not easily explained, became covered toward 
the poles, with an enormous envelope of ice, which after a time, from causes 
also obscure, melted and moved toward the equator, eroding away the upheaved 
prominences and filling up the valleys with clay and other debris that in the end 
left a great area of the country, especially in the Mississippi valley, with the gen- 
eral level surface upon which the rich soil of this great region reposes. 
" The deposits of the drift, as seen in digging wells and making other excava- 
tions, as well as in the precipitous exposures made by water- courses, consist usu- 
ally of a reddish brown clay, underlaid by a bluish plastic clay lying on the sur- 
face of the rock, which is usually reached in both Illinois and Missouri at a depth 
of less than one hundred feet. This depth, however, is sometimes exceeded where 
the valleys of ancient streams are met with. 
" Mingled with these drift-clays are many boulders and masses of rocks of 
great interest from the fact that they are often of different material from any 
rocks we have in place in Illinois. It is quite common to find granite, porphyry ^ 
greenstone and other primary rocks that have evidently come from the region of 
Lake Superior. It is not uncommon to find masses of native copper, doubtless 
from the same northern locality. The present specimens of this copper are from 
the drift in the neighborhood of Alton and near Grafton. It is quite probable 
that a period of many years elapsed — ages, in fact — during the subsidence of the 
drift -glaciers ; and although it may not be quite certainly ascertained that man 
beheld the phenomena of this epoch, it is quite certain that many strange animala 
braved the rigors of the climate and evidently flourished. Some of these animals 
were of strange appearance, and where their bones are discovered protruding 
from the clays, one is astonished at their size. From the clay in the side of a 
ravine in Calhoun Co., Illinois, we recovered the jaw of an elephant beside 
which Jumbo would seem small. One of the teeth from this fossil jaw, and which 
we present for inspection, weighs near eighteen pounds, being much lighter in 
its fossil state than when in the mouth of the living animal. The teeth of this 
grea;t glacial elephant are quite different and much larger than those of .the mastodon 
which also existed during the same period. The teeth of this extinct elephant 
very much resemble the teeth of the elephant of the present day. We have also 
taken from the drift-clays above Alton the teeth and several bones of a huge car- 
nivorous animal allied to the bison, probably the extinct Bos latifrons, the spread 
of whose horns would make those of a Texas steer seem very small in size. 
' ' It is quite probably that during this period more than one species of horse 
existed. Bones of extinct horses are quite numerous in the tertiary deposits 
about the base of the Rocky Mountains. 
"In digging a well in Greene Co., Illinois, the workmen found at the bot- 
tom of the excavation the teeth of an extinct horse somewhat resembling those of 
the present day. We also have seen the fossil tooth of a horse from near Alton. 
