TACIT CA LOIN Ss 864 
Comanche series is in the lithological character of the upper limestones,. 
which are described as compact, gray, more or less silicious, limestone 
with flints, a description that applies equally well to the Caprina lime- 
stone, near the middle of the Comanche series. In the almost com- 
plete absence of fossils, this limestone cannot now be identified with 
the Texan formation from the data furnished by the Mexican geolo- 
mistsa Vie Rote Ell however, in) an ineidentale reference! to) the 
Catorce region, correlates the so-called ‘‘ Hippurites”’ limestone of 
Mexico, whichis probably the same as Castillo and Aguilera’s upper lime- 
stone, with the Caprina. The same author also refers the lower fossilif- 
erous beds of Catorce to the Trinity division of the Comanche series, 
but this reference is based on its stratigraphic position rather than 
either lithological character or faunal contents. From the known dis- 
tribution of the Comanche series in that region it is at least possible 
that portions of the Texan and Pacific coast lower Cretaceous faunas: 
may yet be found in direct statigraphic relation with each other in cen- 
tral Mexico. 
With the occurrence of the Pacific lower Cretaceous fauna at Catorce,. 
not a great distance from the Gulf of Mexico, and of the Texan or 
Gulf fauna in Sonora, much nearer to the Pacific, the question as to 
how the two faunas were kept separate becomes still more difficult. 
From the data now at hand the most plausible hypothesis seems to be 
that the sea transgressed the continent, first from one side and then 
from the other, but never quite crossed the shifting barrier. 
T. W. STANTON. 
Phylogeny of an Acquired Characteristic. By A. Hyatt. Proc. 
Aim, Jelnil, SOE, WOlls XOXO 
Professor Hyatt’s paper “ Phylogeny of an Acquired Characteristic,” 
is essentially a contribution to the philosophy of the Neo-Lamarkian 
school of evolutionists. It is in part a republication in substance of 
several earlier papers, with the matter now put into a more systematic 
shape. While primarily biological it possesses great interest for the 
geologist and perhaps merits a fuller review on that account as it is 
less likely to fall into his hands. 
In the introductory chapter the author lays great stress on the 
importance of the study of the shells of Mollusca. After speaking of 
the relation of the shell to the animal, and of the different structures 
tAm. Jour. Sci., Vol. XLV., 1893, pp. 311, 312, 324. 
