308 0. C. Marsh—New Tertiary Reptiles. 
Oreosaurus microdus, sp. NOV. 
Another species, apparently belonging to the genus Oreosaurus, 
and about as large as O. gracilis, may be established on some 
isolated remains which are quite characteristic. One of these 
is part of a lower jaw with the teeth in excellent preservation. 
The latter are unusually small and slender, and curve gently 
outward. The crowns are nearly round; the summits obtuse, 
somewhat compressed, and marked by irregular striw. The 
5 
jaw is stout, and the groove for Meckel’s cartilage large. 
Width of jaw near middle, . oy hee aeenth» Seok eee: 2° 
Length of lower tooth including base,........... rr 2° 
The only remains that can now with certainty be referred to 
this species are from the Eocene beds, near Henry’s Fork, 
where they were found by the writer, last September. 
Oreosaurus minutus, sp. NOV. 
Measurements. igs 
Space occupied by eight anterior teeth of lower jaw,.---- 22 
Depth of jaw below eighth lower tooth, .........+++-++ 15 
Thickness of jaw at this point, ......0 sescescosrsseesss 
Space occupied by four upper teeth of larger specimen,.-- 2° 
The type specimens of this species were discovered by the 
writer, last autumn, near Henry’s Fork, Wyoming. 
Tinosaurus lepidus, sp. nov. 
A species of very small lizards, apparently belonging © the 
genus Tinosaurus, may be established on some fragment®'y ; 
remains among our Wyoming fossils. One of these 8 ao 
anterior half of a lower jaw in good condition. The pee | 
specimen are compressed, and closely resemble those a — 
chameleon. The rami of the lower jaw were stout, and mi 
