of the Rocky Mountains. 75 
rande occurs north of lat. 49° though it is quite probable that 
when carefully sought after, it will be found revealed along the 
margins of the mountain elevations to the Arctic Sea. 
we proceed southward along the line of the mountain ran 
toward New Mexico, though no fossils have been found, we feel 
safe, acting upon our previous knowledge, in regarding the evi- 
dence as quite clear, that this sandstone occurs in numerous 
evidence, which is the most important, and in most instances the 
only conclusive proof; 2d, Stratigraphical position; 3d, Litho- 
logical resemblance. Th have 
We proceed southward from the Black Hills. Having traced 
Tocks which we regard of this age south to a point on a parallel 
With the Salt Lake district, we present the following resem- 
blances in lithological characters as probable evidence of their 
pa gee in Utah territory. 
bed 
Coarse sandstone or conglomerate which almost invariably ac- 
Companies it. In several localities as at Promontory Point and 
near Mud Island, the metamorphic strata appear to be overlaid 
Y & Coarse conglomerate or coarse sandstone which is partially 
altered and assumes the character of a quartz rock, u in 
the third volume of Pacific R. R. Reports, page 156, mentions 
