361 
1897. 
(Tables V., XIII.; Pl. XXVIII, XLVIIL.) 
There are 24 collections in this year, with an average of 
0.88 cm.’ per m.* as compared with 3.69 in the river, and a max- 
imum of 13.38 on April 27—more than twofold the production 
in the river (5.11) on that day. 
The collections of the first six months of this year are so 
infrequent that the course of production is but slightly indicat- 
ed. In February the production in the impounded waters of the 
winter flood in Quiver Lake (.19) is nearly fivefold that in the 
current-swept channel (.04), while in March there is little differ- 
ence (.34 and .38) in their plankton content. The collection of 
April 27 probably fallsnear the presumably common vernal max- 
imum and in the midst of the decline of the spring flood. Since 
Quiver Lake at the stage of river (11.6 ft.) then prevalent 
contains the run-off of the impounded backwaters to the north, 
it is not surprising that its plankton content (13.38) is more 
than double that of the river (5.11). The similarity in the 
movement of production thus far seen in this year is interrupted 
on May 25 by the decline in the lake to 1.29, while the river 
rises to 5.62. The deeline in the lake may be attributed to the 
great reduction in impounding area due to the decline in levels 
to 8 ft., and to the gain in proportion in the lake of the contri- 
butions of creek and spring water and of the area occupied by 
the now rapidly appearing vegetation. The silt-bearing flood 
of June in the river yields less (.27) than the lake waters (1.26) 
impounded by the rise of the river. 
In the last six months of the year the collections are of 
sufficient frequency to enable us to trace somewhat the move- 
ment in production. This period is marked by a great depres- 
sion in plankton content as compared with that of the same 
season in the previous year, the average for each being 1.06 and 
. 28. The parallelism in the movement of production can still 
be traced in the slight tendency in Quiver Lake to increased 
production in July, September, and November at times of pulses 
