BIOLOGICAL RECONNOISSANCE AT FLATHEAD LAKE. 141 
water, any one of which one might step across. These lead down 
through deep and steep canyons, with dense underbrush, fallen logs and 
boulders. Botanical collecting is good. Insects are not abundant. The 
birds have been noted. The shells have been pretty well worked up, as 
far as species are concerned. 
On the west side there are two large creeks, Dayton creek and Big 
creek. The former enters the large arm of the bay. Lake Ronan, which 
it drains, has not yet been visited. Indeed, no collecting has been done 
on the west bank of the lake. Big creek is near the northern end of the 
lake, flowing into McGovern Bay. At the mouth of the creek there is 
some low and marshy land, small in extent. The lake a few feet off 
shore is deep. The bay near its center is seventy feet deep. 
On the west the mountains come down to the water’s edge as they 
do on the east, though they are not so abrupt nor so high. The reserva- 
tion line passes north of the wide bay at the lower end, thus placing much 
of the Dayton creek low land within the reservation. Settlers have 
taken up land along the lake, on both sides without the reservation lines, 
and the proximity to the lake makes this land very desirable for fruit 
raising. The region about Big creek has not been examined. No ex- 
plorations have been made in the mountains west of the lake. 
As has been stated, the water of the lake is received through the Flat- 
head and Swan rivers. The annual rise of the lake in 1900 was 8.3 feet. 
That year was one of low water. It is claimed by those in a position to 
know that the water has risen as much as seventeen feet during a season. 
Since the lake has an estimated length of about 30 miles, which will for 
convenience be made 25 miles, and an average width of from 8 to 10 
miles, no doubt more than this, it will be seen that the water held back 
by this lake in storage is sufficient to cover an area of from 200 to 300 
square miles to a depth of from 8 to 17 feet. Swan lake, a few miles 
from Flathead lake holds the waters of Swan river in similar manner 
from passing to Flathead lake. 
The amount of water flowing into Flathead lake, or out of it, has not 
been determined. In 1899, two gauges were established on the lake by 
the U. S. Government, one at the upper and one at the lower end. These 
were continued for a little over a year and were discontinued for lack 
of funds. But one measurement has been made of Swan river, none of 
Flathead. 
The air currents of the lake are numerous, and worthy of extended 
study. Rarely is the water perfectly calm. It has been seen, how- 
ever, so still that shore objects were beautifully mirrored. The mount- 
ains on such occasions show up grandly in the reflection. A ride across the 
lake at such time is rare, but it is one never to be forgotten. In the 
evening when much of the pumping was made for entomostraca there 
were many occasions when the water was comparatively quiet. Usually, 
however, a breeze was blowing. 
During the summer the wind on the lake is from the south or southwest, 
the prevailing direction of the region. The general or prevailing winds 
in the summer are as follows: In the morning there is a gentle breeze 
down the lake from the north. Soon this dies away, and the wind 
