446 
2. Bottom Mups oF THE LAKES BETWEEN COPPERAS CREEK DAM 
AND BEARDSTOWN 
Comparison of samples from the central portions of eleven lakes be- 
tween the head of Clear Lake and Browning, May—October, 1914, on 
the dry-weight percentage basis shows the shallow weedy lakes highest 
in bottom nitrogen. The average of Flag, Seebs, and Stewart lakes 
(Class III lakes) in terms of percentage of dry matter, was 0.39%, com- 
pared with an average of 0.27% for seven of the deeper, more open lakes 
of Classes I and II; and with 9. 26% for Crane Lake—a lake of the very 
shallow, very weedy type. The general average of all of the 19 mid-lake 
samples from eleven lakes of 4 of the five classes (0.32%) was some- 
what more than the average for the river channel stations above Havana 
(0.306%) and nearly twice the river average below Havana (0.189% ). 
The general average of organic carbon in mid-lake samples was 3.89%, 
comparing with 2.41% for the river channel above Havana, and with 
1.51% for the channel below Havana. In organic carbon as in nitrogen, 
the shallow weedy lakes of Classes III and IV (with 4.30% and 5.19%) 
averaged well above the deeper lakes of Classes I and II (with 3.67% 
and 3.09%). 
Both in Thompson and Quiver lakes, May—October 1914, the ni- 
trogen and organic carbon figures were considerably highest in samples 
from the shallower water, the percentages of average difference as be- 
tween samples from under and over 6 feet in depth amounting in the 
case of the nitrogen to over 30%, in both Thompson and Quiver lakes, 
and in the case of the organic carbon to 15% in Thompson and to 52% 
in Quiver. 
NITROGEN AND ORGANIC CARBON IN Mups, THOMPSON AND QUIVER LAKES, 
May—Ocroser, 1914 
Nitrogen Organic carbon 
Per cent. Per cent. 
(in terms of dry matter) (in terms of dry matter) 
Thompson Quiver Thompson Quiver 
Lake Lake Lake Lake 
Depth over 7 feet 0.325 , 0.320 4.83 3.46 
Average 8* 4 8 4 
Depth 1—6 ft. 
Average 0.428 0.440 5.56 5.27 
7 4 7 4 
All depths 0.373 0.400 5.17 4.67 
Average 15 4 15 4 
* The Italic figures give the number of samples. 
