TABLE OF CONTENTS. xxix 
Page. 
Wrinkled Strata. 335 
Disrupted strata. 335 
Contorted strata. 336 
Warped surfaces of strata. 336 
(c).Agricultural characters of Helderberg division. 336 
( 1 ) . Corniferous limestone. 337 
Characters. Cyrtoceras characteristic. Used for lime. 337 
Range. Fossils described by Mr. Conrad. Reference to PI. 19, 20 ... 338 
(2) . Onondaga limestone. Description. Favosites and Cyathophyllum.339 
Fossils described by Mr. Conrad. 339 
(3) . Schoharie grit. Local. Orthocera and Pleurorhynchus. 340 
(4) . Cauda-galli grit. Description, range, and fossils. 341 
(5) . Oriskany sandstone. Description and range. 342 
( 6 ) . Delthyris shaly limestone . 343 
(a) . Scutella or sparry limestone. Pelvis of an encrinite and a branched 
encrinite, characteristic. Range of scutella limestone. Same also 
as the upper limestone of Becraft’s mountain. 344 
(b) . Middle limestone. Extremely fossiliferous. Delthyris bilobata one 
of the characteristic fossils. 345 
(c) . Same as the middle limestone of Becraft’s mountain. Characters 
strongly marked, both lithological and zoological. 345 
Fossils described by Mr. Conrad. 345 
(7) . Pentamerus limestone. Description, range. 346 
Lepocrinites gebhardi, characteristic of the middle... 347 
Astrocrinites pachydactylus, characteristic of the base of the group.347 
Section from this rock to Hamilton group. 347 
Fossils described by Mr. Conrad. 348 
( 8 ) . Water-lime group. General description. 349 
Range and extent. Thickness. 349 
^ Upper description and fossils. 350 
Tentaculite limestone, < Middle “ “ 350 
^ Lower “ “ 350 
Water-limestone group. Description and fossils. 350 
Localities of the Helderberg division out of the general range . 350 
1. To-wnsend’s iron mine, Cornwall, Orange county. 351 
2 . Becrafi’s mountain. 351 
3. Mount Bob. 351 
4. Ontario division . 353 
( 1 ). Pyritous strata, and red shales and grit. 353 
Section near High falls. 353 
Use of pyritous limestone. 354 
Pyritous stratum at Schoharie and other localities. 354 
