GEOLOGY DEVONIAN. 21 
between Troublesome and Hunter creeks shows greenstones, cherts, sheared chert 
conglomerate, and slates, with disconnected limestone masses in which fossils deter- 
mined as Devonian were found. The chert conglomerates are frequently found in 
close association with the limestones, and at the locality where Devonian corals were 
collected conglomerate with chert and quartz pebbles is found in close association 
with the limestone, which also contains quartz pebbles. 
Most of the rocks encountered in the Rampart region are a continuation along the 
strike of those occurring in the section from the White Mountains nearly to Yukon 
Flats. There are the same lithologic types, the same associations, and, so far as the 
meager fossil evidence is available, it corroborates the relationship of the rocks in 
the two areas. 
Following is the list of fossils collected by the party. The determinations were 
made by Mr. E. M. Kindle, of the United States Geological Survey: 
Fossils from the Wliite Mountains. 
4 AP 240. This lot contains two corals, a Michelina and a Zaphrentis, neither of which 
is specifically determinable. Horizon probably Devonian. 
4 AP 241. Favosites near epidermatus occurs in this collection indicating a horizon of 
Middle Devonian age. 
4 AP 242. Specimens of a coral comparable with Favosites winchelli comprise the 
collection from this locality. Horizon probably middle Devonian. 
4 AP 243, 245, and 246. These several lots represent the same horizon. The fauna 
as represented in the collection comprises a single species of brachiopod Gypidula 
of pseiido-galeatus. The horizon represented is either late Silurian or early Devo- 
nian, probably the latter. 
4 AH 186. Includes only poorly preserved specimens of Cladopora. Probably of 
middle Devonian age. 
4 AH 193. The fossils represented are Cytherella sp., Cladopora sp., and Ftilodictyaf 
cf. frondosa. The horizon is probably Silurian. 
4 AH 194. Favosites near lirnitaris occurs in this lot, indicating a horizon probably 
near middle Devonian. 
4 AH 195. Contains an undetermined Stromatopora, Age probably Devonian. 
Fossils from the Rampart region. 
4 AP 303. Two poorly preserved specimens of Aulacophyllum comprise this lot. The 
horizon represented may be either Devonian or Silurian, so far as the evidence 
from this material indicates. 
4 AP 317. Minute fragments of small corals in a breccia comprise this lot. Fossils 
too fragmentary for determination of the age. 
CARBONIFEROUS. 
At the extreme northern limit of the hill country, in a minor ridge bordering 
Yukon Flats, there are greenish, grayish, and black slates, with siliceous material, 
scattered fragments of which were found to contain fossils indicating a Pennsylvanian 
or Permo-Carboniferous age. At another locality, about 15 miles to the southwest, 
just south of Hess Creek, fossils also regarded as Carboniferous were found in soft 
black carbonaceous shales. At both localities the rocks are in close association on 
the south with cherts and slates, and it is possible that some of the cherts may be of 
Carboniferous age. All that can be affirmed at present is that in the northern part 
of the area there occur Carboniferous rocks, whose extent and relations to the rocks 
of Devonian age are not yet determined. 
The following fossils, determined by Mr. George H. Girty, were collected at the 
two localities and the discussion of them is quoted from his report. 
