THE PERMIAiSr EEMNANTS. 
103 
so-called Permo-Carboniferous beds of King and Gilbert. But Mr. Walcott, 
finding their fauna more closely allied to the Permian, and, in fact, very 
strongly distinguished from or even contrasted with the true Carboniferous 
beneath, has wisely, as it seems to me, included them in the Permian of the 
Plateau Province as its basal division. Some conception of the manner in 
which the remnants of this formation occur may perhaps be gained by im- 
agining a country which is nearly a smooth plain and only diversified by 
wide flat-topped eminences 80 to 150 feet high, separated by broad shallow 
valle3^s. Conceiving the strata to be everywhere horizontal the eminences 
would correspond to the remnants of Lower Permian strata, while in the 
valleys the summit of the Carboniferous is laid bare. 
In the southern part of the Uinkaret there are several masses which 
are much more than low eminences, which in fact attain nearly or quite 
the dignity of mountains or at least of very large hills, and which preserve 
the entire Permian series with thick bodies of basalt overlying it. Two of 
these are especially noteworthj^ The loftiest and most conspicuous is 
Mount Trumbull, a broad, well-defined, and isolated mass rising nearly 
2,000 feet above the plains at its base and nearly 3,000 feet above the Toro- 
weap Valley near its southeastern flank. It consists of Permian strata which 
liave here a thickness of probably 1,400 feet with a basaltic lava cap 500 
to 600 feet thick forming the upper part of the mountain. In all strictness 
it is a great butte. Its strata are sensibly horizontal, and the whole mass 
has very plainly been carved out like a cameo b}" the denudation of the 
strata roundabout. Two or three miles southwest of Trumbull is Mount 
Logan, a tabular mass of much greater area but somewhat lower in altitude. 
In respect to structure, it is veiy similar to Trumbull, having nearly if not 
quite the whole Permian series, with a lava cap of varying thickness, but 
seldom exceeding 300 feet, and usuall}^ from 100 to 200 feet thick. South 
of Logan and distant about five miles is a platform which may perhaps 
be regarded as the continuation of the Logan mass in that direction. A 
depression exists between the two sufficient to warrant a topographical 
distinction if we desire it, though not so great as to destroy entirely the 
continuity of the two if we prefer that view of the case. This southern 
platform has apparentl}^ a structure similar to that of Trumbull and Logan, 
