176 SNAKE RIVER PLAINS OF IDAHO, 
[BULL. 199. 
charge is small. One of the stronger of these wells delivers in August 
a gallon of water in seven minutes, and is said to discharge about a 
gallon per minute in winter. Neighboring springs have various tem- 
peratures, ranging from 56° to 59° F. 
These shallow wells, some of which began to now when a depth of 
60 to 70 feet was reached, are in a broad, deeply alluvial-filled valley 
and evidently depend for their water supply on an alternation of per- 
vious and impervious beds in the alluvial deposits. The source of the 
water of the several cold springs is, no doubt, the creeks which flow 
from the mountains southward, but the wells must be supplied from 
a deeper source. 
Little Valley is situated within the Lewis artesian basin, and at a 
lower level than the surface at the flowing wells near Hot Spring 
post-office, in Bruneau Valley, but the wells referred to above do not 
furnish a test of what may be termed the true artesian condition. 
The partially developed hot spring in the upper portion of Little 
Valley, described above, is about a mile east of the shallow artesian 
well just referred to, and presumbly derives its water from a deep 
source. 
ROCK CREEK HILLS. 
In the valley of Rock Creek, about 3 miles south of Rock Creek 
post-office, Cassia County, on Mr. E. M. Crockett's ranch, a 6-inch 
well put down in 1899 has a depth of 275 feet. The water rose at 
first to a height of about 20 feet above the surface, but owing to leak- 
age due to imperfect casing has since ceased to flow. The water stands 
about 3 feet below the top of the well. 
Half a mile south of the Crockett well, on Jones Brothers' ranch, 
two wells drilled in 1899, each 6 inches in diameter, imperfectly cased, 
now discharge about 2 cubic feet of water per second . The temper- 
ature is about 75° F. , but was not measured. One of them is 90 feet 
deep, and the other, 30 yards distant, 115 feet deep. 
The three wells on Rock Creek are situated in a deep canyon- like 
valley among hills of stratified rhyolite, where the rocks have been jj 
considerably disturbed. No structural artesian basin is definitely 
known to be present, but further study may show that this region is 
an extension eastward of the Lewis artesian basin. Springs are 
numerous in the same region and supply Rock Creek, w T hich flows 
throughout the year to below Rock Creek post-office, where its water 
is all used for irrigation. 
The geologic conditions in the Rock Creek Hills are closely similar 
to those in the rhyolitic mountains to the north of Mountain Home, 
where springs are also abundant, and the success of the wells drilled 
at the former locality suggests that equally favorable results should be 
expected on Long Tom and Syrup creeks and about Mount Bennett. 
In the neighborhood of the Rock Creek Hills several borings have 
