MAMMALIAN REMAINS 
129 
rhombic calcite crystals which are bronzed with limonite; 2, oc- 
casional tabular and fanshaped aggregates of barite crystals. 
The mode of formation is obscure. 
Department oe Geology, 
Iowa State College. 
NOTES ON SOME MAMMALIAN REMAINS REPORTED 
IN IOWA DURING THE PAST YEAR 
A. O. THOMAS 
Road-making activity, the . opening of new gravel pits and 
drainage ditches, and natural erosion have brought to light an 
unusually large number of fossil bones. A large ditch near 
Avoca has yielded an excellent skull of the giant beaver, Cas- 
tor oides ohioensis, and at the same place a humerus of the great 
ground sloth Megalonyx. From Wayland comes a perfect tibia 
of the same kind of sloth and near it was found the crown of an 
unerupted mastodon molar. A well preserved, but worn down, 
tooth of the Columbian elephant was found in a gravel pit at 
Hartley and a part of a tusk at Bellevue. The skull of a large 
elk bearing a fine pair of antlers was taken from near the base 
of the Des Moines river bank at Irvington. The skull of a small 
deer from a gravel pit at Eddyville completes the list. Illustra- 
tions. ■ 
Department op Geology, 
State University op Iowa. 
