1885.] Geology and Paleontology. 385 
the face of the great degradation of these peoples the English 
missionaries assert the language of the Yahgans contains no less 
than 30,000 words, “ suggesting the hypothesis of an origin very 
different and far superior to their present state.” 
GEOLOGY AND PALAIONTOLOGY. 
Tue Otpest Tertiary MammaLia.— The lowest horizon of the 
Puerco epoch of New Mexico has recently been explored by 
David Baldwin with good results. The following is a list of the 
species of Mammalia obtained by him. The proportion of nov- 
elty, it will be seen, is large: 
Polymastodon ? taoénsis Cope. 
Polymastodon latimolis, sp. nov.—This marsupial equals the P. 
faoénsts in size, and is therefore larger than either the P. fissidens or 
the P. foliatus, It differs especially from both the P. taoënsis and 
the P. foliatus in the great shortness of the first true inferior 
molar, which is only one-half longer than the second or last true . 
molar. The latter is as wide as long in the type, and a little nar- 
rower in a second specimen. Ft supports four tubercles on the 
inner side; outer side worn. The first true molar appears to have 
five tubercles on the inner side, although the anterior edge is in- 
jured. In P. ¢aoénsis there are six or seven. The fourth premo- 
lar is two-rooted. The enamel of the last inferior molar is faintly 
longitudinally wrinkled. The coronoid process rises opposite the 
middle of the second true molar, 
Measurements: Total length of molar series, M. .038; of sec- 
ond true molar .017; width of do. .o11; length of crown of sec- 
ond true molar .014; width of do. .o11. Depth of ramus at M. 
II .038; do. at diastema .024. Depth of ramus of a second indi- 
vidual 042. Besides the shortness of the second true molar, the 
width of the same tooth and of the last true molar distinguish 
this species from the Z. taoénsis. The inflection of the angle of 
the ramus of the lower jaw is as well marked as in other species 
of the genus. : 
Chriacus hyattianus, sp. nov.—Represented by two maxillary 
bones with molar teeth, one of which is accompanied by a broken 
Mandibular ramus, which supports the second true molar and 
parts of other teeth, The superior molars are quite peculiar, and 
are especially characterized by their small transverse as compar 
with their anteroposterior diameter. The crowns are surrounded 
by a cingulum, except on the inner side, where distinct traces of 
it are visible. The external cusps are small and low and flattened 
on the external side, and are connected at their bases by a low 
ridge. They send inwards each an angular ridge which unites 
with its fellow in an angular internal cusp of little elevation, en- 
closing a triangular fossa. Small angular intermediate tubercles 
exist at the internal bases of the external cusps. The posterior 
cingulum is a little better developed than the anterior, and rises 
VOL. XIX,—No, IV, 25 
