46 (©. Barrois—Review of Professor Hall’s recent volume 
In this work, the Devonian fauna of the State of New York 
is divided as below, in the descending order. 
Catskill Group. 
Chemung ‘ 
Portage : 
Genesee slates. 
Hamilton “ Hamilton beds. 
Marcellus shales. 
§ Upper Helderberg limestone. 
Upper Helderberg Group. 4 Schoharie Grit—{Calcareous sandstone). 
( Cauda-galli grit. 
This group of formations is mostly limestone at the base, 
while slates and sandstones prevail in the upper part. 
the Cauda-galli grit and the Catskill group we shall not have 
occasion to refer, as these divisions do not contain representa- 
tives of the forms treated of in this volume. The Schoharie 
same epoch that they appear in the greatest abundance. In 
Germany the Platyceras and the Platyostoma characterize the 
sandst n the west of France they abound in the “ Her- 
nien” limestones of Erbray and also in the Devonian lime- 
sto of Courtoisiéres, ete., while they are wanting in the 
teristic of the Hercynien epoch; one cannot distinguish the 
living Capulus from the Devonian Platyceras, and many 
* The French of Dr. Barrois is here literally followed in making the name of 4 
genus a noun of multitude. 
