58 The American Naturalist. [January, 
triangular shape, confluent at its base with the distal facets, as seen in 
T. cornutum Osborn, of the lower Uinta. In the small species T. meg- 
arhinum Earle, the primitive type persists through to the Lower 
Uinta, with some lengthening of the neck of the astragalus and of the 
sustentacular oval. A Bridger specimen of T. cultridens is more ad- 
vanced, being intermediate between megarhinum and the supposed 
hyognathum. Diplacodon in the Upper Uinta, shows a short neck, 
but the facet was long elliptical, tending towards confluency ; it ap- 
pears more nearly allied to the persistent primitive forms than to — 
either extreme type, as shown in T. cornutum on the one hand and P. 
paludosus on the other. These characters of the foot-structure appear 
to be mainly dependent on the size of the animal and are, therefore, of — 
little taxonomic value; but there appears to be a valid distinction be- — 
tween the long-footed Telmatotheres and the short-footed Palseosyops, — 
which may serve as a further reason for separating the two genera. — 
It must be remembered, however, that intermediate forms were abund- — 
ant, and gave rise, probably, to the later Titanotheres. 
In all but two of the above mentioned species the foot material is — 
associated with skulls more or less complete. The determinations of — 
the latter are on the authority of Osborn and Earle, and they will be _ 
fully described by Prof. Osborn in a forthcoming paper, this note, by 
his kind permission, being published in advance.—W. D. MATTHEWS. 
The Western American Læœss.—In a paper read before the : 
Iowa Academy of Sciences Mr. B. Shimek states that his investigations 
concerning the deposition of the Læss of Iowa have convinced him 
that the theory of the lacustrine origin of the deposit and its origin in 
violent fluviatile floods are equally untenable. He offers instead the 
theory that the less is of æolian origin, and that it was deposited 
principally in forests amd to a lesser extent in dense growths of smaller 
plants, while proportionately small quantities only were carried 
directly into the waters and there deposited. 
The author adduces the following facts to show that the loss is not 
of aquatic origin : 
“ First.—The land area during the period of the formation of the 
loess was large as is shown by the remains of great numbers of terres- 
trial mollusks.” , 
“Second.—The occurrence of dry region mollusks, many of which 
species are now living TATEN Iowaand eastern Nebraska, particu- 
larly in wooded regions.” 
Sar ee nea ee OE tae EN E AAA ae 
E E oo Sin Sate Ih tat gtk a E MER aria, Ole gto ct Cope Prat PI 
