xx PROCEEDINGS. 
etc. He noted that these deposits in lakes on different sides of the 
same watershed were characterized by the presence in more or less 
abundance of some peculiar species. He was endeavoring to obtain 
sections of some of these deposits so as to be able to compare the varia- 
tion of or succession in the species since the first deposits were laid on the 
barren beds of the lakes carved out in the glacial period. Over a 
hundred different species had already been observed in our fresh water 
deposits, many of them identical with those found in similar deposits 
in the Eastern hemisphere. Among them were found the silicious 
spicules of several species of freshwater sponges, which appear 
to be also more or less abundant in all our freshwater deposits. The 
following species of diatoms have been already identified in these 
deposits : 
Cocconeis pediculus, Hhr. CC. placentula, #hr. Gomphonema 
acuminatum, Hhr. G. a, var. coronatum, Atz, G, a. var. laticeps, Hhr. 
G. cristatum, Ralfs. G. gracile, var. naviculoides, Grun. G. abbrevia- 
tum, Ag. G. capitatum, Hhr. G. intricatum, Atz. G. cistula, Hemper. 
Epithemia turgida, Hhr. E. gibba, Ehr. E. g. var. parallela, Gran. 
E. argus, Zhr. Himantidium arcus, EKhr. H. a. var. majus, W. Sm. 
H. a. var. tenellum, Grun. .H, formica, Ehr. HH. pectinale, Kitz. 4H. 
p- var. ventricosum, Grun. H. p. var. minus, Atz. H. p. var. undula- 
tum, Ralfs. HH. soleirolii, Kitz. H. bidens, W. Sm. 4H. b. var. diodon, 
Ehr. HH. praeruptum var. inflatum, Grun. H. polydon, Brun. H. 
polydentulum, Brun. Amphora ovalis, A¢z. A. affinis, A¢z. Cymbella 
gastroides, Atz. C. cuspidata, At¢z. C. ehrenbergii, A?z. C. lanceolata, 
Ehr. C. delicta, A. Sch. C. cistula, Hemper. C. heterophylla, Ralfs. 
C. tumida, Atz. N.ambigua, Ehr. N. appendiculata, Aéz. N. affinis, 
var. amphirhyncus, Ehr. N. firma, Grun. N. Hitcheockii, Hhr. N. 
legumen, Hhr. N. dicephala, Atz. N. radiosa, Kéz. N. scutellum, 
O'Meara. Pinnularia oblonga, Rab. PP. viridis, Rab. P. v. var. 
hemiptera, Rab. PP. perigrina, Hhr. P. nobilis, Ehr. P. major, Rab. 
P. dactylus, Atz. P.gibba, Ehr. P. divergens, W. Sm. P. interrupta, 
W. Sm. P. mesolepta, Hhr. P. nodosa, Ehr. Stauroneis phoeni- 
centeron, Ehr. St. gracilis, W. Sm. St. anceps, Hhr. St. fulmen, 
Breb. St. punctata, At¢z. St. stauropheria, Hr. Surirella robusta, 
Ehr. S. splendida, Hhr. S. biseriata, Breb. S. bifrons, Aéz. S. 
turgida, W. Sm. S. linearis, var. constricta, W. Sm. S. slevicensis, 
Grun. S. elegans, Hhr. S.-tenera, Grey. 8. cardinalis, A‘dtton. 
