;}7() The American Geologist. Dccoiiii)^!-, is95 
the Washita. Some of the rocks in wliicli it occurs in iiorth- 
Avestern Texas should possibly be referred to the upper por- 
tion of the Bosque division. The description and illustrations 
of the little round-ribbed shell called Jfn(//<>/i/ ciniccuh'ice- 
costrlhihi in Koemer's KreidebihlaiKjcn is, on stratigraphic 
grounds, suspected to have been based on small and ])Oorly 
preserved specimens of this species, liut only the fact that 
the types of Dr. Koemer's species came apparently from 
within the stratigraphic range of M. stojieiraJlensi.s would 
ever lead one to suspect this, so widely different is the char- 
acter of the ribs, as illustrated, from the concentric ornament- 
ation of ModioUi stonewalleii.sis. 
CiKMiIIa'a recedens is common to the Fredericksburg and 
Denison divisions. The writer has collected it in the AValnut 
and Comanche Peak terranes of the former and in the Choctaw 
terrane of the latter. 
JSfucnla cafhei'iiia is reported by Prof. Hill as having been 
" identitied in the Washita division of the North Texas region." 
It would be interesting to know what terrane and locality of 
that division yield it, as it is a fossil common in both the 
Kiowa shales and the Mentor beds. If the terrane that yields 
it in the North Texas region be the Kiamitia, which Prof. 
Hill calls a Washita and Mr. Taff calls a Fredericksburg 
terrane, its " Washita" occurrence means simpl}^ occurrence 
in a group of sediments intermediate between Fredericksburg 
and Washita, the Kiowa group, which is about equally related 
to the Fredericksburg and to the Washita; but if it be one of 
the Denison division, it occurs above the true Washita. 
Yoldia microdonta in northern Texas, is a Denison division 
fossil, being common in the Pawpaw beds. In central Kansas, 
it is a fossil of the Mentor beds. 
Trigonin emoryi, unlike the Denton marl species, 2\ clavi- 
gera, is probably common to the Fredericksburg and Washita, 
and not improbably to the Denison also. It was observed by 
the writer in limestone of the Walnut zone of the Fredericks- 
burg in 1890 when, in company with Prof. Hill, he was leav- 
ing Weatherford enroute for Granbury. The species is 
extremely common in some localities in the Walnut claj^s of 
the Fredericksbui'g. Twenty-five well preserved specimens of 
it from these clays are before tln^ writer, which were his share 
