SS, , ZIBB corpus iS 2S 
Geological Survey of the Territories in 1872. 205 
t. 
A few miles north of the north end of the lake, the Tetons 
begin to rise from the flat divide of Falls River; and their 
slopes show Silurian and Carboniferous limestones overlying 
the central mass of metamorphic strata, as on the western side 
of the range. The Potsdam quartzite was not seen here, but is 
probably in place. The knobs of the central portion of the 
valley still show some of the volcanic rocks, though these oc- 
_ outlet was found to have been consequent upon the influx into 
the old channel of the sediment-bearing stream escaping from 
that here opens out of the mountains. A small lake, hemmed 
in by the terminal moraines of that ancient glacier, now fills 
the mouth of the valley. A similar lake lies before the valley 
which receives the entire drainage of the western side of the 
principal peaks of the Tetons; but it is not surrounded by any 
conspicuous moraines; and it is questionable whether the more 
ther south, and are surrounded, the first by five and the second 
by three large moraines. 
he Teton range, as seen from the west side of Jackson's 
Lake, is a grand one, rising as a wall to heights varying from 
5000 to 7000 feet above the level of the plain. he sno 
Patches were already on the increase (Sept. 24th,) and occa- 
sionally nae would make the range really snow-covered, 
w hours 
sandstones, probably of Tertiary age, appear ae 
the stream, for a shoe distance ; but no rocks are then visible, 
until the point is reached, about twelve miles up stream, where 
