284 The American Geologist. November. 1902 
one is not represented in the southern loess, and but very spar- 
ingly in that of the north. The common and characteristic 
species of the loess, not only at Natchez but in all the Missis- 
sippi valley, belong- to the other section of the genus, of which 
S. ohliqiia, S. grosvenorii and i". avara are members, and all of 
these are upland species, or at least are commonly found on 
higher grounds, — and none of them are in the remotest sense 
aquatic or "semi-aquatic." Viewed in the light of the quota- 
tion from the London Times, the deposit in which the pond 
snails were obtained can scarcely be referred to typical loess. 
The ocurrence of the fish-bones is unique and throws no light 
on the prevailing loess conditions. Such limited quantities oi 
material might have been carried to the highlands by birds or 
mammals, and subsequently buried deeply by dust. 
[NIcGee also says* that this loess "yields . . . shells of land 
snails sometimes associated (particularly at lower levels) with 
shells of water snails and other fluviatile moUusca." Xo names 
are given, and the reference is probably based on Lyell's state- 
ments. The same is probably true of the following reference :t 
"The loess is unusually rich in shells of land and swamp mol- 
lusca, together with a few aquatic species." 
Altogether the evidence of the occurrence of aquatic shells 
in the southern loess is very unsatisfactory. They certainly 
cannot be very abundant or widespread if among the 4600 
specimens collected by the writer there is not one aquatic shell. 
The occurrence of vertebrate remains in the southern loess 
is quite as doubtful. Lyell's fishes have already been dis- 
cussed. He had previously stated li: that the shells already noted 
are "associated with bones of mastodon, elephant, tapir, and 
other megatherioid mammals." Again, in the Principles of 
Geology § he says: "As to the mammalia of which some bones 
have been found in the lowest part of the loess and in clay at 
its base, they are many of them extinct species. Among them 
are Mastodon gigantciis, a species of Megalonyx, a Mylodon, 
Bison latifrons, Equns anicricanus, Felis atrox, two 
species of deer, two of bear and other quadrupeds, some ex- 
tinct and others still living." 
*p. 393, 1. c. 
tp. 399, 1. c. 
tAthenEeum, ]84(). 
§P. 4G1.' 
