SCUDDER. ] TERTIARY LAKE BASIN OF FLORISSANT. 291 
ments of leaves of Phragmites; of Filices, numerous specimens of a 
single species; of Rhizocarpae, many specimens of Salvinia Alleni, de- 
scribed from Florissant and Elko, Nev.; of Musci, Hypnum Haydeni, 
likewise known only from this locality; and of Characeae, two speci- 
mens of a Chara. 
Mr. Lesquereux has also found large numbers of leaves of a peculiar 
plant without any kind of neuration, which is apparently referable to 
the Proteeae. 
We have thus from 90 to 100 species of plants already recognized from 
these Florissant beds, of which nearly half the species belong to the 
apetalous exogens. About 40 of the species are figured in the Tertiary 
Flora of Lesquereux. 
According to this writer, such an assemblage of plants indicates a 
climate like that of the northern shores of the Gulf of Mexico at our 
epoch. ‘The preponderance of conifers, of shrubs, * * * of trees 
of small size, * * * gives tothe flora a general aspect which recalls 
that of the vegetation of uplands or valleys of mountains.” Palms are 
almost entirely absent, only a single specimen of one species of Sabal 
having occurred. “Theleaves of some species are extremely numerous, 
none of them crumpled, folded, or rolled, as if driven by currents, but 
flat, as if they had been imbedded in the muddy surface of the bottom 
when falling from the trees or shrubs along the borders of a lake.” 
It is remarkable for the almost complete absence of hard fruits; and 
this, with the presence of flowers, of unripe carpels of elm and maple, 
and of well-preserved branches of Taxodium, which in the living species 
“are mostly detached and thrown upon the ground in winter time or 
early spring,” led Mr. Lesquereux to believe that the deposition of the 
vegetable materials took place in the spring time, and that the lake 
gradually dried during summer. 
To this we may add that the occurrence of Acorus, of Typha, and es- 
pecially of Potamogeton, leads to the conclusion that the water of the 
lake was fresh, and not saline or brackish, equally proved by the fish, 
according to Cope, and by the presence of larvae of Odonata and other 
insects whose earlier stages are passed only in fresh water. 
Neither the groups of fishes which have been found, nor the water- 
plants, the water-insects, nor the mollusks exclude Mr. Lesquereux’s 
suggestion of the annual drying of the body of the lake. Moreover, cer- 
tain thin layers are found overlying coarser deposits, which are sun- 
cracked through and through; but on the other hand the thickness of 
the paper shales, upon which most of the fossil remains are found, and 
which are composed of uniform layers of triturated flakes of volcanic 
products, being necessarily the result of the long-continued action of 
water, excludes this idea. The structure of the rocks rather indicates 
a quiet deposition of the materials in an unruffled lake through long 
periods, interrupted at intervals by the influx of new lava-flows or the 
burying of the bottom sediments beneath heavy showers of volcanic 
ashes. 
The testimony of the few fishes to the climate of the time is not unlike 
that of the plants, suggesting a climate, as Professor Cope informs me, 
like that at present found in latitude 35° in the United States; while 
the insects, from which, when they are completely studied, we may cer- 
tainly draw more definite conclusions, appear from their general ensem- 
ble to prove the same or a somewhat warmer climate. If we inquire 
what testimony the fossil spiders of Florissant bear to the climate of 
that district in tertiary times, there is only one answer to be given; the 
present distribution of their allies certainly points to a considerably 
