132 ALASKAN MINERAL RESOURCES IN 1906. 
schists and limestones occur. In accounting for this he points to the 
contacts of different kinds of rock and the immediate vicinity of such 
contacts as loci of maximum weakness and greatest adjustment when 
the rocks are subjected to disturbing forces, as a result of which a freer 
circulation is there possible for mineral-bearing waters. This relation 
has been brought to the attention of the writer also by mining men in 
Nome and should be kept in mind by prospectors, since such contacts 
are favorable localities. Heavy limestones are found in the southern 
part of the mineralized area of Anvil and Glacier creeks, and thinner 
beds occur in the ridge between the two streams. • To the northwest, 
however, their number decreases, and here some of the greatest min- 
eralization is seen. It does not appear, then, that in this last-named 
place the presence of limestone was essential to the formation of min- 
eral deposits. In fact, it would be difficult to prove that the lime- 
stone-schist contacts to the southeast are more highly mineralized 
than the schists themselves, but the occurrence of nearly all the placer- 
gold deposits of the peninsula in such areas suggests the relationship 
mentioned. Buster Creek affords a good example of a disturbed lime- 
stone-schist area where small secondary quartz deposits are numerous. 
UNCONSOLIDATED DEPOSITS. 
( i EN ERAL DESCRIPTION . 
Unconsolidated deposits may here be divided into two classes — 
those which have undergone a sorting process and deposition in water 
and those which have not. To the first class belong present stream 
and lake gravels, bench gravels, and the gravels of the Nome tundra 
to the second, the loose debris mantling the slopes of hills and derived 
from the decomposition and weathering of the rock beneath or on tbj 
slopes above, together with part of the morainic material resulting 
from glacial action. 
In by far the greater number of small streams the gravels consist o: 
material like that of the hills surrounding the valley and appear to be 
entirely of local origin — that is, they are derived from bed rock in the 
drainage basin where they now lie and within a comparatively shor 
distance of their present location. 
In the larger streams, such as Nome, Snake, Stewart, and Sinu] 
rivers — that is, in streams heading toward the Kigluaik Mountains- 
together with a few of their tributaries, and in the Nome tundra a con 
siderable portion of the gravel is derived from a more distant source 
and its distribution is such as to indicate that part of it was laid dow 
under conditions different from those prevailing at the present time. 
Rounded granite bowlders derived from some source in the Kigluai 
Mountains are found in Sinuk and Stewart River valleys, along Snak 
River, on Anvil and Dexter creeks, along Nome River, and at varioi 
