THE 
JOURNAL OF GEOLOGY 
SHPTEMBLER-OCTOBER, 1600 
THE OZARKIAN AND ITS SIGNIFICANCE IN 
THEORETICAL GEOLOGY. 
I. THE OZARKIAN. 
In 1886 I published a paper entitled ‘“‘A Post-Tertiary Eleva- 
tion of the Sierra Nevada, as shown by the River-beds.” ' Again 
in 1891 I published a paper on “ The Mutual Relations of Land 
Elevation and Ice Accumulation during the Quaternary Period.”? 
The following paper may be regarded as a continuation of the 
lines of thought suggested by the two preceding. 
By continued reflection on the enormous changes that 
occurred in the western part of the continent at the end of the 
Tertiary, I have been led to recognize the existence of an epoch 
of long duration and of great importance immediately preceding 
the time of the invasion of the ice sheet. On account of its 
great importance this epoch certainly deserves a distinctive name. 
For want of a better, I adopt that of the ‘ Ozarkian,” given it 
by Hershey. , 
Ehstory of the name.—The epoch was first recognized by Hil- 
gard and more distinctly by McGee, as the post-Lafayette uplift, 
*Am. Jour. Sci., Vol. XXXII, p. 167, 1886. 
? Bull. Geol.. Soc. Am. Vol. I, p. 329. 
Vol. VII, No. 6, 525 
