234 Scientific Intelligence. 
ridge on the under surface. The shaft is hollow, and the walls 
are thin and smooth. The outer condyle is placed obliquely, 
as in the Cretaceous species, and the lower groove between the 
two condyles is unusually narrow. The inner condyle is nearly 
circular in vertical outline, and its articular portion extends 
over about three hundred degrees 
The principal dimensions of this specimen are as follows: 
Length of portion preserved ---- -- 32-0"™ 
Transverse diameter of shaft where broken _.__.-. 4°5 
Anitero-posterior diameter -._.... 22.2.2. .2222-1- 
Transverse diameter of shaft immediately below 
BONG VIS SCS 
? 
Antero-posterior extent of outer condyle -_.------ 75 
This interesting specimen was discovered in the Atlanto- 
saurus Beds of Wyoming, by Mr. 8. W. Williston. Its generic 
relations cannot at present be determined, but the species repre- 
sented may be named Pterodactylus montanus. 
Yale College, New Haven, August 17th, 1878. 
SCIENTIFIC INTELLIGENCE, 
1. Descriptive Geology ; by Arnotp Hague and 8. F, Emons; 
Vol. Il of Geological Reports of United States Geological Explo- 
ration of the 40th Parallel, CLareNncE Kina, Geologist-in-Charge. 
890 pp. 4to, illustrated by 26 plates. Washington, 1877. Sub- 
mitted to the Chief of Engineers and published by order of the 
sults was expected for another number. The expected article has 
not been received; and as the volume is of special importance In 
connection with American Geology, a notice is here given without 
further delay. 
The region explored is a very extended one, it reaching from 
the eastern Colorado range to the Sierra Nevada, with a width of 
about a hundred miles along the 40th parallel. The authors state 
that the seven years engaged in the work, from 1867 to 1873, was 
sufficient to make only a geological reconnaissance, rather than a 
. 
finished systematic survey. Still, the account of the region is 
f 
e of such 
the whole is presented so clearly and systematically, both as 
regards the physical aspect, topography and geology, the general 
