Beview of Recent Geological Literature. 107 
same manner as Murchison and Verneuil, but that by Foster 
and Whitney these are specially exempted. The Azoic sys- 
tem, as defined by Foster and Whitney, would be the equiv- 
alent, nearly, of the recently named Keewatin and Vermilion" 
groups, and, until fossil remains have been found in the 
Animike (Huronian), it would also be considered to embrace 
that. If the Animike be finally shown, as suspected, to be the 
equivalent of the "Olenellus beds" of the Taconic, it would 
have to be excluded from the Azoic. There is a pliability con- 
sistent with possible future discovery, in the definition of the 
Azoic by Foster and Whitney. But this is wanting in the 
Century definition. According to it the Azoic rises to the 
Potsdam sandstone ; and the remarkable statement is made 
that it (we understand the Potsdam sandstone) is "the lowest 
group of rocks which has up to the present time been proved 
to contain traces of a former organic life." Shades of 
Emmons and Barrande ! What can now be done with the 
"Olenellus beds?" Where shall Linnarson and Brogger, and 
Nathorst, and Salter, and Hicks, and Walcott, and Ford, and 
Matthew now assign the great fauna th sit they have discovered 
in strata below the Potsdam. 
REVIEW OF RECENT GEOLOGICAL LITERATURE, 
Contributions to the micropaleontology of the Cambro- Silurian rocJcs of 
Canada, Part ii. E. 0. Ulrich. Geol. Sur. of Canada, 1889. 
The paper describes specially somepolyzoa (bryozoa) and Ostracoda 
from Manitoba, the new forms being Monticulipora parasitica var. 
plana, Diplotrypa westoni, Batostoma maijitobensis, Petigopora 
scabiosa, P>ythopora striata, Fistulipora? laxata, Gomotrypabilateralis, 
Pachydictya bexagonalis, and P. magnipora, Ptilodictya whiteavesi, 
Lejierditia subcylindrica, Primitia lativia, Primitia ( ? lieyrichia) 
parallela, Eurychilina reticulata, and E. manitobensis, Strepula huaa- 
tifera. The forms are illustrated bj' two plates. 
The fossils from Stony mountain indicate the upper part of the Hud- 
son River group. Those from St. Andrews indicate the Trenton. 
Kentucky fossil shells, from the Silurian and Devonian rocks of Ken- 
tucky. By IIknryNettlerotii. Kentucky Geological Survey. J. R. 
Proctor, director, 4to„ pp. 295, and iJG plates of fossils, $5.00. Robert 
Clarke & Co., Cincinnati, O., and John P. Morton & Co. Louisville, Ky. 
This monograph contains a short sketch of geology and palocontology, 
giving the outlines of both sciences, explaining the principles upon 
