506 MORRIS M. LEIGHTON 
Association for the Advancement of Science which he read at the 
Minneapolis meeting. Quoting from this paper’ we read: 
The drift clays proper at Alton, Illinois, had a maximum thickness of 
about one hundred feet, and the bluff clays were nearly of the same thickness. 
These clays were remarkably rich in animal remains, such as teeth and bones, 
attached to calcareous nodules or claystones. Remains of thirteen different 
species, now perhaps all extinct, had been found. The rodents were well 
represented by bones of seven species, including three or more beavers and 
some gophers. Nearly seventy teeth were found in the Quaternary deposits, 
a majority of them in a single quarry. 
The locality—The blufis northwest of Alton have a height 
of from 125 to 175 feet above the Mississippi River. Approxi- 
mately 75 to 125 feet of the section is Mississippian limestone, 
while the overlying material consists largely of loess with a thin 
deposit of glacial till in places separating the loess from the lime- 
stone. The upper surface of the limestone is somewhat uneven, 
but the cliffs persist for many miles up the river. Just east of 
Alton’ the Mississippian formations give way to the Pennsylvanian 
sediments. The upland of the western part of the city is charac- 
terized by karst topography, due to the solvent action of ground 
water on the underlying Mississippian limestone. 
Section at one of the quarries—At Plant No. 2 of the Mississippi 
Lime and Material Company, northwest of the roundhouse, the 
following section was found: 
Feet 
Soil, loessial, dark brown, leached. .. , I 
Loess, brownish at the top, grading below iia a few 
feet into buff; leached 4 to 5 feet below the soil; calcare- 
ous below, with a few loess fossils scattered through the 
deposit; stands with steep face in fresh cuts; maximum 
thickness amee : . about) 2o 
Loess distinctly more resdien ciel the onesie. strongly 
suggesting a distinct deposit; contains many fossil 
snails, some “‘pipestem”’ concretions; has a silty tex- 
ture but not sandy; maximum thickness . . about 30 
Glacial till, reddish, contains many erratic pebbles of 
granite, dolerite, greenstone, quartzite, and other Canadian 
rocks, and also some local rocks, mostly subangular, some 
t Proc. A.A.A.S., Vol. XXXII (1883), pp. 268-69. 
