392 The American Geologist, December, 1894 
cushion as thf Laramie, and there are few concerning which there are 
still so many questions of interest undecided. As has long been known, 
the correct delimitation of this formation is a matter attended with 
some difficulty. It has been thought thai the Laramie strata represent 
unbroken sedimentation from the Cretaceous into the Eocene. Cross, 
Eldridge, and Hills, have shown that there is in Colorado a series of 
post-Laramie beds of considerable extent, which are separated from the 
true Laramie by marked unconformity. It has been found that many 
of the plant remains, supposed to represent the Laramie, in reality be- 
long to the Denver and correlated beds. The necessity of a careful re- 
vision of these forms has been insisted on. Similar beds and relations 
have been found in Canada. These facts impart a considerable interest 
to the results obtained by a study of the intervening Montana field. 
In brief, Mr. Weed finds near Livingston, Montana, overlying the 
coal-bearing Laramie strata and underlying the Fort Union beds, a vast 
series of sandstones, grits, clays, and agglomerates, aggregating some 
7,000 feet in thickness. This series is separated from the true Laramie 
by unconformity, and is characterized by a distinct flora. It consists of 
upper and lower beds, between which is intercalated, over a portion of 
the field, a 2,000 foot bed of subaerial, volcanic agglomerates, composed 
mainly of andesitic lavas. 
The evidence of unconformity consists of observations by Dr. A. C. 
Peale near Sphinx mountain, where the beds referred to the Livingston 
were seen to rest in angular unconformity upon the Dakota sandstone; 
certain irregularities in the thickness of the Laramie; and the presence 
in the Livingston of pebbles derived from all the earlier formations, 
whereas the Laramie contains Archean debris only. From these obser- 
vations it is inferred that when the Laramie beds were being deposited 
Archean land only was exposed, but that before the Livingston epoch 
the land was elevated and during that epoch all the earlier beds were 
undergoing erosion. The debris, mixed in part with andesitic lavas 
from the neighboring volcanoes, was laid down in an inland lake. 
Mr. Knowlton has carefully revised all the plants from these beds; a 
work of considerable difficulty and necessity. In all he finds some 44 
species. Of these 5 are new, and 11 are not found elsewhere. Of the 
remainder 22 are Livingston forms, 2 Laramie proper, and 4 common to 
both. Of the 22 species having distribution outside of this area, 17 are 
exclusively Denver forms or have their greatest development in that 
formation. 
The Fort Union beds are recognized as Eocene on both stratigraphic 
and paleontologic data. u. f. b. 
Geology <>f tin- Big Stunt- (hip Coal Field nf Virginia and Kentucky. By 
&LUUU8 R. CAMPBELL. (U.S. Geol. Survey. Bulletin 111. 106 pp.: 6 
plates, and 3 figures in the text. 189:5. Price, 15 cents.) The area 
studied and described in this report is one which, although long famous 
in history and more recently familiar to the tourist, has been almost 
unknown geologically. The Carboniferous strata of Pennsylvania. Ohio, 
