Cope.] 472 [Aug. 15, 
M. 
leone Lu OL centrum DOlOW.;.24 neice eas 0.009 
Depth to base neural spine, in front.................- Dia 
WECUN GUUS tay aie eo els Ginn ta erie eco 0054 
DeDU, cter ee Ot a e 0045 
iixpanse parapophyses above... ........:... cesses ee. 012 
nf ie DOLOW Cr ree tert ie. 008 
ON A NEW GENUS OF PLEURODIRA FROM THE EOCENE 
OF WYOMING. 
By Epwarp D. Corr. 
(Read before the American Philosophical Society, Aug. 15, 1872.) 
The following observations are made with a view of establishing the 
stratigraphic position of the genus of tortoises described below. They 
were made by the writer while prosecuting a palacontological investiga- 
tion of the Tertiaries of Wyoming for Dr. F. V. Hayden’s Geological 
Survey of the Territories, 
The strata exposed along the northern and eastern shores of Bear River, 
consist of alternate sandstone, argillaceous, and conglomerate rocks of 
the Wahsatch Group of Hayden. They dip to the northeastward. At 
the coal mines below (7. ¢., N. W. of) Evanstown, the series is capped by 
a heavy bed of conglomerate. At a point seven miles above (7. ¢., S. E. 
of) Evanstown, the strata appear in the following order: (1.) an argilla- 
ceous rock just appearing above the river level at high water ; (2.) 25 feet 
of sandstone ; (3.) a nodular argillaceous rock of a red and ochreous 
color, 15 feet; (4.) 10 feet of coarse conglomerate; (5.) 80 feet of sand- 
stones and clays, 
At a point eleven miles above Evanstown, the conglomerate has 
descended from view, and the bluffs of 800 feet in height, consist of the 
upper members of the group, viz.: red and white argillaceous beds; 
sandstone four to six feet in thickness; a red and white argillaceous 
stratum, at least forty feet ; sandstone 3-4 feet, and a capping of a hard, 
brittle, ash-colored clay rock on the highest points. Ascending five miles 
further to the N, E., the strata are observed to dip in a direction opposed 
to those at Evanstown, rising gently to the N. E. One of the heavier 
sandstone strata is exposed about half way up the bluffs, and is visible 
in the side ravines. Crossing one of these, and climbing the opposite 
spur, a sandstone identical lithologically with those just described, is seen 
standing vertically ; and succeeding spurs are crowned with the edges of 
the succeeding sandstone beds standing high inthe air. Nearly opposite 
Beartown, a mile eastward on the Union Pacific Railroad, these vertical 
sandstones pass into a conglomerate, one of the strata being composed 
equally of both, a gradual lithological transition being exhibited. 
