6 
Dtilletin of the Natural History Society. 
tions of material from the base to the summit of the lacustrine 
deposit. These collections which exhibit the whole series of layers 
in the deposit, from the Saxicava or Macoma sand upward, have since 
been examined in a general way, and a synopsis of the results obtained, 
in so far as they relate to the Land vegetation, and the fresh-water 
plants of the order Characeae^ are given in the following pages, together 
with valuable notes on the Characese from the pen of Dr. T. F. Allen of 
New York, a celebrated writer on these low forms of vegetable life. 
As the investigation of the deposit of the lake is not yet com- 
pleted, I shall only give at present a brief outline of the physical 
aspect of the formation, chiefly to elucidate Dr. Allen’s notes on the 
Characere. 
Before my examination of the lake deposit it was not suspected 
that any lacustrine beds other than the marls existed there, the 
underlying clays being supposed to be marine ; but it was found 
that the pure shell-marl formed relatively less than a half of the whole 
lacustrine deposit, where it is accessible along the present margin of 
the lake. Several pits were sunk through the fresh-water 
deposit, and the most complete series of beds observed is that given 
in the following section. The numbers indicate groups of beds 
which have a common physical aspect, and the letters a thickness in 
each case, with a few exceptions, of about 3 inches of the deposit. 
No. 1 a Marine sandy clay (Saxicava or Macoma sand) with marine 
molluscous remains of species found in the Upper Leda-clay and 
Saxicava (Macoma) sand. 
No. 1 h 
No. ^ ah G 
No. 3 a 6 
No. 4 a 6 
V Lacustrine clay. 
No. ^ ah Lacustrine peat, 
No. ^ ah G d 1 -D , 1 
^ 0.1 abcde I Peaty marl,. 
No. % ah G d e ) -r, i 
AT n z. j > Fure marl, , 
No. ^ah Gdef g ) ’ 
17 inches. 
3 “ 
25 
36 “ 
81 
The whole lacustrine deposit rests everywhere upon the Saxicava 
sand which owing to the sheltered position in which it was accumu- 
lated is largely mixed with clay, to this cause probably is to be 
