BIOLOGICAL RECONNOISSANCE AT FLATHEAD LAKE. 99 
Our camp at this lake was from July 7 to July 18, 1900. The party 
numbered 15 most of the time, and for a couple of days there were 23, 
including a number of distinguished visitors. The weather was perfect, 
not a thing to stop work for the entire time. 
A second visit was made in June, 1901, a month earlier than in tha 
preceding year. A large collection of plants was made and further notes 
and collections of shells were taken. Dredgings were made for Ento- 
mostraca in the lake and in the ponds to the south of the lake. As the 
season was early there was much moisture. This made the material 
collections more abundant but made the work more laborious. 
On the north side of the lake the mountain rises abruptly to a height 
recorded by our aneroid as 9,200 feet, probably 200 in excess of the true 
height. On the summit abundance of snow could be seen. The lower 
slopes are moderately wooded with small red fir, while the upper heights 
are bare jagged rocks. On these a few white-bark pine have a foothold. 
See Plate XXIV. On the east and south of the lake the summits are lower, 
sloping gradually to the south and then to the west where the ridge des» 
cends almost to the level of the waters of the lake. The mountain sides 
in this direction are densely wooded with small trees. The western end 
of the lake is the only part with what might be termed open country. 
Here the lake is dammed by a moraine which is now covered with small 
trees and other vegetation. This moraine extends across the ravine, which 
is here about a quarter of a mile in width, and down stream for nearly a 
mile, as nearly as could be determined. The present outlet is at the south- 
ern end of the moraine. There are indications that the outlet was formerly 
at the other end of the moraine, next the mountain side proper. From in- 
dications it would appear that the lake was formerly larger than at pres- 
ent, when the waters were dammed up, overflowing what is now the 
good camping place, and for some distance beyond. On the moraine tha 
vegetation is different from that at other places, indicating that the period 
when the waters covered this part of the moraine is not so very far back 
in time. The time that has elapsed since the outbreak at the present 
outlet has not been great. When the lake occupied this addition it was 
larger, and perhaps forty or fifty feet deeper. When the water first 
started at the present outlet the cutting was rapid, as shown by the 
abrupt and narrow declivity at the outlet, and resulted in the present 
lake level. 
By damming up the present outlet the level of the lake could be raised 
about fifty feet without overflowing the moraine. 
The lake is about 7,500 feet long and 2,500 feet wide. The shapa 
and outline are readily seen from the accompanying sketch. See Fig 1. 
The length lies east and west. The lake is clear, cold, and deep. At 8 
P.M., July 9, 1900, the temperature was 15 degrees Centrigrade. By 
trials it was found that the white net used for collecting entomostraca 
could just be seen at a depth of 30 feet. The dark rocks on the bottom 
could be seen only at much less depth than this. 
The banks of the lake are precipitous, no shoals or rocks being found. 
The largest shallow place is on the western end of the southern side 
where a small shallow place some 300 feet long by 50 feet wide slopes 
