160 ALASKAN MINERAL RESOURCES IN 1906. 
these bowlders have been brought by glaciers from Kigluaik Mountains 
and carried into their present position by ice blocks floating on a lake 
formed by glacial obstruction of the drainage. This suggestion is tc 
be regarded only as a working hypothesis, but it fits in with the knowr 
facts, which may be summarized as follows: The angular, un weath- 
ered form and foreign character of the granite and the presence oi 
shore lines at considerable elevations. Lakes of this type are com- 
mon in regions that are at present glaciated, and evidences of such 
lakes have been recognized in many places where glaciers have no\* 
disappeared. 
GENERAL GEOLOGY. 
The bed rock of the district belongs to the Nome series. It consists 
of a series of much faulted and contorted limestones and schists and 
some greenstones. The greatest development of limestone occurs ir 
the lower part of Iron Creek, but a great number of thinner beds inter- 
laminated with schists are encountered even up to the headwaters 
It is believed that the numerous alternations of schist and limestone 
are indicative of the source of the Iron Creek gold. Although nc 
extensive proof of mineralization at the limestone-schist contacts has 
been found in this locality, the fact that such contacts are the loci oi 
mineralization has been very well established in other parts of Sewarc 
Peninsula. 
The rocks of the Iron Creek district trend northeast and southwest 
and dip t< >ward the southeast, but there are numerous exceptions to this 
general direction, as the rocks are complexly folded and faulted. The 
deformation and consequent shattering that the rocks have undergone 
has undoubtedly resulted in the formation of zones of pervious rocH 
in which mineralization has taken place. The streams also have taker 
advantage of the northeast-southwest structure and practically all the 
tributaries are arranged parallel to this direction. 
rn lithologic character the rocks are similar to the Nome series as 
described for other parts of the field. The schists present two mair 
lithologic facies, namely, graphitic and chloritic. No boundary 
between the two can be drawn at the present time, although it is 
believed that detailed study would solve their interrelation and struc 
ture. The chloritic schists are most extensively developed in Iroi 
(reek below Telegram Creek. They are thinly laminated, with wavi 
cleavage, and rusty brown to greenish gray in color. Chlorite ane 
quartz are the only minerals distinguishable in the hand specimen 
Graphitic schists are most abundant on Telegram Creek above Eldorad< 
Creek. These rocks are in general but slightly schistose and woule 
better be described as dark, nearly black, graphitic quartzites, witl 
here and there schistose phases. Hand specimens show considerable 
quartz and a little chlorite. The other constituents are not distin 
guishable by the eye, though the presence of graphite is recognizee 
