572 REVIEWS 
The correlation of the various deposits with those of other regions 
is cautiously discussed. The Patuxent is correlated with the Trinity 
of Texas, the Lakota of the Black Hills, the Kootenai of Montana and 
British Columbia, parts of the Shasta group of the Pacific Coast, the 
Kome beds of Greenland, and possibly with the Morrison of the Rocky 
Mountains. The Patapsco is probably of the same age as the Fuson 
formation of the Black Hills, and parts of the Lower Cretaceous of the 
Gulf and Pacific coasts. The data are too meager to attempt correlation 
of Upper cretaceous deposits. The Aquia and Nanjemoy are correlated 
approximately with the Wilcox and Claiborne of the Gulf region. 
BeAg Ss: 
The Mount McKinley Region. By ALFRED H. Brooks. With 
Descriptions of the Igneous Rocks and of the Bonnifield and 
Kantishna Districts by L. M. PrinpLe. Professional Paper 
70, UES: G:S52p234 exes igo: 
The field work for the report was done in the summer of 1902. 
Extreme difficulties were encountered, but in spite of them a distance 
of 800 miles was covered by the party of seven men in 105 days. Aside 
from the geological and economic discussions, the report includes a 
detailed narrative of the trip, a review of previous explorations and 
surveys, and a valuable statement of the complete equipment. 
All rocks older than the Devonian are greatly metamorphosed and 
include undifferentiated sediments, with some igneous rocks that are 
thought to be Paleozoic. Rocks that may be still older than these are 
micaceous, graphitic, and quartz schists that occur in the northeastern 
part of the Alaska range and in the Yukon-Tanana region. The Ordo- . 
vician rocks are blue limestones with black carbonaceous argillites, 
siliceous limestones, and calcareous slates, occurring along the north 
front of Alaska range. Some green argillites and cherts of 4,000 feet 
thickness are of uncertain age but are tentatively called Devonian or 
Silurian. The Devonian is represented by 200 feet of heavy fossiliferous 
limestone, 2,000 feet of chert, quartz conglomerate, sandstones, and 
slates, together with some volcanic rocks which may belong to the 
Carboniferous. 
The Mesozoic group is abundantly represented by Lower, Middle, 
and Upper Jurassic rocks of great variety and thickness. There are 
remnants of igneous activity at the base and the top of the Jurassic. 
