PALEONTOLOGY OF NEW-IORI. 
The descriptions and illustrations of the fossils in the third volume of 
this work include those from the Lower Helderberg group and the Ori¬ 
skany sandstone; while the first part of the present volume, following 
the formations in the ascending order, will embrace the Brachiopoda of 
the following rocks and groups : 
CHEMUNG GROUP; 
PORTAGE GROUP, The Genesee slate, forming beds of passage; 
Cauda-galli grit, which rests upon the 
Oriskany sandstone. 
The Cauda-galli grit is almost a non-fossiliferous rock; a few frag¬ 
ments of plant-like fossils, and the peculiar surface markings of the slaty 
laminae, from which the name is derived, being the only objects resem¬ 
bling organic bodies which have fallen under my observation. A single 
specimen of Platyceras, similar to P. tortuosum of the Oriskany sand¬ 
stone, has been found in this rock. 
The passage from the Oriskany sandstone to this “ Grit,”' or (as it 
usually occurs in many localities) arenaceous shale, or shale, is very 
abrupt and strongly defined. The rock itself is usually a dark or nearly 
black slaty grit, weathering to a grayish or brownish gray color, with 
strong lines of jointing or lamination nearly at right angles to the bed- 
[ Paleontology IV.] 1 
