212 MEMOIRS OF THE CARNEGIE MUSEUM 
Besides this especially favored locality other places have been found, which have 
yielded interesting White River fossils. Some of them have been mentioned in 
previous articles. Among the new localities found are those at (a) Cafion Ferry, 
near the Missouri River east of Helena, (b) between Prickly Pear Creek and the 
Missouri River northeast of Helena, and (c) near Dogtown Mine near the wagon 
road from Three Forks to Boulder. At Cafion Ferry the most of the fossils were 
from the Oreodon horizon ; though the beds a little to the north and northeast prob- 
ably belong in part to the Titanotherium horizon. With one or two exceptions, the 
fossils from the other localities above mentioned, belonged to the lower beds. 
Icrops. 
The type of Ictops is I. dakotensis. It was found in the Bad Lands of White 
River, Dakota, in 1866, and was described by Leidy in 1868. I quote from Leidy’s 
description. 
“ Ictops dakotensis. This name is founded on a small fragment of a skull which 
was obtained with the preceding [ Leptictis haydeni]. At first the specimen was sup- 
posed to belong to the same animal as the former. It clearly indicates a skull of 
nearly the same size and shape as that of Leptictis. 
“The fragment consists of a portion of the face, containing the remains of most 
of the molar teeth. The face appears to have had nearly the same form and con- 
struction as in Leptictis, and the forehead exhibits traces of the two peculiar ridges 
defining the upper part of the temporal fossa in the latter. 
“The remains of the molars consist of the posterior six. The second premolar 
appears to have been a two-fanged, conical crowned tooth, as in Leptictis. The third 
premolar has a trihedral crown, inserted by three fangs, whereas in Leptictis, as in 
the preceding tooth, it has a simple conical crown with a pair of fangs. 
“The crown of the third premolar of Ictops is composed of three principal lobes, 
two external and the third internal. The four back molars have the same relative 
position and size as regards one another as in Leptictis, but they do not project 
abruptly beyond the premolars externally as in this. Their crowns, so far as can be 
ascertained, appear to have had the same construction as in the third premolar. 
“The space occupied by the back six molars in Jcfops is ten lines, being a little 
more than Leptictis.” 
Leidy called these two genera “insectivorous mammals, which appear to be 
peculiar, but related to the hedge-hogs.”’ ? 
In his Extinct Mammalian Fauna, p. 351, Leidy describes Ictops a little more 
fully, and figures what is undoubtedly the type (Plate XXVI., Figs. 29 and 30). 
' Proc. Acad. Nat. Sci. Philad., 1868, p. 316. 
