628 The American Naturalist. [July, 
denudation has in many cases afterwards brought them to the surface. 
M. Calderon conckides with these words : " I do not think that it will 
be too bold to conclude, as a general law, that when a saliferous forma- 
tion, rich in marls and clays, magnesia and gypsiim, is exposed to tan- 
gential force, it must produce the epigenic phenomena known as ophitic, 
and give birth to true massive crystallized rocks in its anticlinals. 
Vertebrata of the Swift Current River.— No. III.— My 
second contribution to the knowledge of the fauna of the White River 
Miocene, as exhibited at the above locality, appeared in the Natural- 
ist of the present year, p. 151. The researches of Mr. T. C. Weston 
during the past season, under the direction of Dr. Selwyn, Chief of 
the Survey, have added a number of interesting points to our know- 
ledge of the fauna, and the following new species : 
Menodus selwynianus sp. no v. — Represented by a nasal process, 
which consists of the coossified nasal bones, of peculiar form. They 
are elongate as compared with their width, and are vaulted. The 
lateral borders are nearly parallel, and the extremity viewed from 
above is rounded. Owing to the thickness of the body, the profile 
descends abruptly at the extremity, and the convex surface is rough- 
ened as though for the attachment of some fixed body, tegumentary 
or muscular. From this tuberosity the surface descends steeply to a 
thin border. A short distance posterior to the extremity the lateral 
margins are decurved, forming the lateral walls of a deep longitudinal 
median gutter-like nasal meatus, which is deeper than in any other 
species. The horns are broken off, but the median inferior surface is 
so little recurved laterally, that it is evident that the former were not 
only small, but laterally placed. Length of fragment above, mm. 130 ; 
length of nasal border, 70 ; width at nasal notch, 80 ; do. near 
extremity, 65 ; depth at apical tuberosity, 26. 
This species is dedicated to Dr. A. R. C. Selwyn, the accomplished 
director of the Survey of Canada. 
Menodus syceras sp. nov. — This species belongs to the group with 
muzzle and horns of moderate length — the central group of Scott and 
Osborn. It differs from the two species of that group now known, 
the M. proutii Leidy, and the M. tichoceras S. and O., in the very 
close approximation of the basis of the horns, and the presence of a 
strong angle or ridge connecting them, so that the nasal bones are in 
a different plane from that of the front. The entire width of the 
skull at the basis of the horns is not greater than the length of each 
horn above the nasal notch. The horns are not long, and the section 
of their base is a longitudinal oval, flattened on the external side. 
