WARD.) JURASSIC CYCADS FROM WYOMING. 387 
A somewhat careful section was made east of the eycad locality at 
the point where the spur attains it greatest elevation, which is where 
it suddenly breaks away and exposes its western end down to the level 
of the low ridge holding the cycadean trunks. The following is the 
section: 
Section of the Freezeout Hills, Wyoming. 
Cretaceous capping CCN (oe nS cease RED eee ee 50 
Fresh-water Jurassic (190 feet) : 
Top of cycad stratum to base of Cretaceous.............------eeeee eee eee 100 
CY CAC satiatitin jt semitone evs oes d ata gacneeanpeeewentaneuan a a.cane 10 
Top of marine Jurassic to bottom of cycad stratum................-----.-. 80 
Marine Jurassic from Red Beds exposed in bottom of valley to base of fresh-water 
SUIT ASSI Ch ic a carats dla ter Gaeeasen els mab ecrenahee ow etd CNN Hen yet 115 
LOGI Exposure ns cc wcusc se alae oniediccalclauuiine soe sanguine nee 855 
The fresh-water Jurassic consists of fine soft sandstones, white, red- 
dish, or yellowish, and olive-gray calcareous shales, at nearly all parts 
of which occur lenses or extensive beds of dark marls holding saurian 
bones and other vertebrate remains in great numbers. Some of these 
occupy a position above and others below that of the cycad-bearing 
stratum, and a number of bones were found in the cycad bed itself at 
its eastern end. These, however, may not have been in place, as no 
marls occur at this point. 
I may add that there was no part of the section that is not practi- 
cally paralleled in the Black Hills, and it does not differ more in gen- 
eral geological character or in the thickness of the several members 
from those I made in several parts of the Black Hills than those 
sections differ from one another.*' The conclusion seems inevitable 
that practically the same general geological conditions obtain over a 
vast region of the Rocky Mountain uplift. Not less important to the 
paleontologist is the other general inference which so naturally flows 
from all the facts observed, that the life, both animal and vegetable, 
of this enormous period, extending, apparently unbroken, from the 
Permian to the Tertiary, has left its record, and will ultimately be 
known with a high degree of certainty. The marked difference that, 
we shall presently see to exist between the cycadean forms of the 
Jurassic and those of the Lower Cretaceous fully attests the rapid 
change that took place during the comparatively short interval that 
separates them. 
The material collected on this expedition was shipped to the National 
Museum by Mr. Charles Schuchert, who was a member of the party. 
Several other trunks were collected by Mr. Charles Gilmore before 
my arrival, and are at the University of Wyoming awaiting shipment. 
These I have not seen, nor have I had time since my return to study 
1See Nineteenth Ann. Rept. U. S. Geol. Survey, Part II, pp. 5b4-.568. 
