120 ALASKAN MINERAL RESOURCES TN 190G. 
water under pressure brought by ditches or pipe lines to hydraulic 
giants is the method most generally employed. 
Little mining was done on Resurrection Creek during the season of 
1906. A dredge installed in 1905 did not prove a success. The shal- 
lowness of the ground and the presence of bowlders of such size as to 
effectually prevent successful operation appear to have led to this 
result. 
A hydraulic plant on Rainbow Greek, which enters Turnagain Arm 
on the north opposite Resurrection Creek, was not working during the 
past season. 
Developments on a large scale were made on Crow Creek, a north- 
west tributary of Glacier Creek, which enters Turnagain Arm on its 
northern shore 8 J miles east of the town of Sunrise. The Crow Creek 
Consolidated Mining Company began operations June 6, a large 
hydraulic plant having been installed under exceptional difficulties at 
a point a short distance above the junction of Crow and Glacier 
creeks. 
The deposit being mined, aside from its economic value, is of con- 
siderable interest in a study of the development of the adjacent region. 
The following points are to be noted: First, a rock gorge of consider- 
able depth cut in bed rock; second, the gorge, as well as a considerable 
extent of territory on each side, filled or overlain by a notable thick- 
ness of water-laid sands, silts, and gravels; third, recent stream action, 
superimposed upon these gravels, cutting through them, and forming 
the present gorge, now far below the older one. 
It seems reasonable that the cutting of the first gorge may be 
referred to preglacial stream action. The glacial striae and rounded 
surfaces on the exposed bed rock below the pit at the old level of 
erosion are excellent evidence of the former presence of the ice. The 
encroachment of the ice down the main valley of Glacier Creek and 
the accompanying occupancy of Crow Creek by a glacier would 
account for a cessation of the cutting of the old gorge. It is assumed 
that either the mass of the trunk glacier acted as a barrier while the 
side gulch was already clear of ice, or lateral morainal deposits from 
the trunk glacier were sufficient to dam the valley of Crow Creek, 
offering an opportunity for the filling of the old valley of that stream 
by a process of intermittent flood and low-water deposition. The 
character of the sediments exposed in the upper pit would strongly 
suggest such an origin for them. Moreover, the cemented condition 
of the old gravels lying immediately next the old bed-rock surface ia 
evidence of a quiescent stage in their history such as might occur were 
they buried in a lake deposit. The erosion of a new channel througM 
this thickness of gravels, sands, and silts, with the consequent forma- 
tion of the present gorge, was the final step in the history of this creek. 
The following is a description of the lant: Water is supplied by a 
