FRESH WATER DIATOMS. 
319 
determined. The deposits at this locality are remarkable for 
their purity and whiteness, though owing to the presence of an 
apparently silicious cement, they are difficult to separate and 
clean. The locality in which they are found is probably nearly 
1,000 feet above the sea, and the lake bottom occupies an area 
of 122 acres, now laid bare by draining. The depth of the 
Tripolite varies from 8 to i6 feet. Probably 50 acres of it are 
from 15 to 16 feet deep. The upper portion to a depth of 3 to 
12 inches is of a gray colour, soft and mushy with some 
vegetable fibres, while below this the material is sufficiently firm 
for horses to walk upon it though possessing a springy character 
suggestive of rubber. This portion is pure white and destitute 
of fibres. 
Diatoms from Cover Lake, North Branch of the Little S. W. 
Miramichi. 
Stauroneis phoenicenteron. 
Stauroneis anceps. 
Pinnularia viridis. 
Pinnularia major. 
Pinnularia mesolepta. 
Eunotia monodon. 
Eunotia diodon. 
Eunotia tetraodon. 
Himantidium gracile. 
Himantidium undulatum. 
Tabellaria flocculosa. 
Tabellaria fenestrata. 
Cymbella Ehrenbergii. 
Cymbella cupidata. 
Navicula'binodis ? 
Navicula. 
Navicula amphigampus. 
Navicula elegans? 
Navicula ovalis. 
Melosira aurichalcea. 
Surirella ovata? frag. 
Cocconeis. 
Epithemia Argus. 
Epithemia alpestris? 
Gomphonema capitatum. 
Encyonema. 
Cocconema lanceolatum. 
Cocconema Cistula. 
Synedra ulna. 
Fragillaria Harrisonii. 
