254 The American Geologist. April, 1891 
Pearl lake is about one and one-third miles in diameter and the 
ice has been known to crowd up on the shore over 40 feet in three 
months when clear of snow, which would average 5 to G inches a 
• lay. But when covered by a few inches of snow the ice will re- 
main stationary all winter, because the snow is a non-conductor 
and prevents the changes of temperature from affecting the ice. 
Although the movements of the ice in the existing glaciers of the 
world have been studied by the most scientific men of the age and 
man}* theories have been advanced as to the cause, it seems plain 
to me that there can be but one cause, viz. : contraction by cold and 
expansion by heat ; and the fact that ice remains inactive when so 
covered as not to feel the changes of temperature goes to prove 
that were the temperature to remain uniform for any length of 
time in the region of a glacier its movement would cease. 
NOTES ON THE GEOLOGY OF THE SOUTHWEST. 
By Robert T. Hill, Austin, Texas. 
Gold in Indian Territory. — The occurrence of gold in the In- 
dian Territory has been the cause of periodic mineral excitements 
for several 3*ears. The writer has had occasion during the past 
year to examine the regions wherein the gold occurs. There are 
two of these, one near Tishomingo in the Chickasaw Xation and 
the other in the Wichita mountains upon the Comanche Reserva- 
tion. In both localities the conditions are favorable for mineral 
deposits, consisting of igneous contacts of granite and eruptive 
material with numerous veins and faults, accompanied b} T large 
deposits of debris derived from them, sufficient to warrant investi- 
gation for placer deposits, in the Tishomingo district at least. 
The just rights and well founded opposition to investigation of 
the present Indian proprietors prevent an}- careful exploration, 
while even reconnoissance is accompanied by danger. 
The mineral resources of Texas are the subject of considerable 
inquiry owing to recent official promulgations from the office of 
the state geologist concerning the occurrence of tin (cassiterite) 
platinum, and lengthy communications in the press of the state 
upon the value of the woody lignites aud Eocene greensands. 
While it is apparent upon the face of these announcements just at 
the beginning of a session of the Legislature, that their purpose is 
not altogether scientific, it is to be doubted if it is a wise policy 
