46 
rugenious sandstone, which contains a multitude of 
other fossil remains, particularly a large species of 
Productus and of Terebratula. »It is said to have 
been found in Ulster county, in the State of New 
York, by the late Charles Wilson Peale, Esq., the 
distinguished founder of the Philadelphia Museum. 
During the memorable search after the bones of the 
Mastodon Giganteum, in the marl pits of that county, 
this enterprising naturalist procured our Asaph with 
many other remarkable petrifactions. The rocks 
which contain them were probably found not in situ, 
but were masses rolled from the neighbouring Shaw- 
angunk mountains,* which by some geologists are 
supposed to be a link in the grand chain of the Alle- 
ghanies. Mr. R. Peale, of New York, lately visited the 
rich repository of fossils in Ulster County, and pro- 
cured a number of specimens of the A. Laticostatus, 
all of which he has kindly permitted me to examine. 
These are much smaller than our cast, but in many 
instances the caudal elongation is perfectly de- 
veloped. The A. Laticostatus also occurs in the 
Helderberg mountains, specimens of which are in the- 
Albany Institute. } 
Asapuus Srrenurus.t Laton. Casts Nos. 14 & 15. 
Cauda semilunari; costis angustis, valde distinctis; 
abdominis articulis duodecims corpore convexo. 
* The Lenape tribe of Indians, who formerly inhabited this 
district of country, gave the name of Shawangunk to this stu- 
pendous ridge of hills—a name which has been hii er i 
served. | | 
t Derived from Sake, moon, and ouros, tail. 
