38 The Ajncrican Geologist. July, uvyy 
the isthmus of Tehuantepec in Mexico and to certain high ter- 
races in the Adirondacks and the mountains o*' New England 
as being phenomena identical in kind and due to the same 
causes as the channels and terraces of the bd^ce region. But 
such arguments involve obvious fallacies. For the high ter- 
races of the Adirondacks and New England are not like the 
beaches of the lake region — they are certainly not wave made, 
but are apparently stream made, probably by border drainage 
along the edge of the ice — and it is hard to consider seriously 
the suggestion that the col channels of our glaciated area were 
necessarily measured and cut on the pattern of more or less 
similar channels in the tropics, and under conditions controlled 
bv identical forces. The answer to all such suggestions is that, 
as facts now stand, the evidence which has been gathered with- 
in the Erie-Huron-Ontario area itself is essentially complete 
and conclusive — not, of course, in all minute details, but in 
all those larger facts which are recjuired for general interpre- 
tation. So it really makes no difference wdiat is found in the 
Adirondacks or New England or in ^^lexico; facts from those 
regions can have no real bearing or weight as against the 
complete solidarity of the case which has been made out for 
ice-dams within the Great Lake area itself. 
ORIGIN AND AGE OF CERTAIN GOLD "POCKET" 
DEPOSITS IN NORTHERN CALIFORNIA. 
By O. H. Hershey, Freeport, 111. 
The north central portion of Trinity county, in the heart of 
the Klamath system of mountains in northwestern California, 
is occupied by a nucleal series of bare granite peaks, the loftiest 
portion of the so-called Coast range of the state. Roughly 
stated, they form a dissected plateau with an average altitude 
of say 5,000 feet, that of individual peaks being over 7,000 feet 
the highest of all, Mt. Thompson, reaching about 9,125 feet, 
above the sea. That portion of the group which lies west of 
Trinity Centre and Minersville, is abruptly terminated on the 
eastern and southern sides, and the culminating point. Granite 
peak, over 8,000 feet in altitude, overlooks a broad basin made 
up of ridges rising to 3.500 and 3,700 feet, separated by nar- 
