192 GEOLOGY OF OHIO. 



The insufficiency of the evidence upon which the conclusion is based 

 that the Sandusky limestone belongs to the Hamilton group will be seen 

 from the range of most of the fossils which form this evidence. For ex- 

 ample, Cyrtia Hamiltonensis is found throughout the Corniferous, Hamil- 

 ton, and Chemung. The same is true of Atrypa aspera. Atrypa reticularis 

 ranges from the Clinton to the Chemung. Athyris spiriferoides is found 

 throughout the Corniferous and Hamilton groups. I should also say that 

 Cyrtia Hamiltonensis occurs in abundance at Sylvania, at the very base 

 of the Corniferous group, and I have well-marked specimens from that 

 locality obtained by Mr. Gilbert in limestone that was somewhat inter- 

 stratified with the Oriskany. 



This subject will be found discussed more at length in Vol. L, Part I, 

 pp. 144-149, and the reader is also referred to the reports on Delaware and 

 Paulding counties by Prof. N. H. Winchell, contained in this volume, and 

 to that of Mr. S. K. Gilbert on Lucas county, Vol. I., Part I., p. 576. 



The fossil fishes of the Corniferous limestone have attracted more or 

 less attention from geologists for many years. They are now chiefly ob- 

 tained from the quarries on Kelly's Island and Marblehead, in the 

 Lower Corniferous limestone ; in those of Sandusky and Delaware, from 

 the upper member, or Sandusky limestone. My attention was first called 

 to them by Dr. E. S. Lane, of Sandusky, as early as 1850. Since then a 

 great number of fine specimens have been obtained from the Sandusky 

 quarries by Dr. Lane, Dr. A. H. Agard, and Mr. L. P. Wheelock. These 

 represent quite a number of genera and species, which are figured and 

 described in the palasontological portions of this and the preceding vol- 

 ume. The following is a list of such fossil fishes as have been found at 

 Sandusky and on the islands : 



Macropetalichthys Sullivanti .'....Newb. 



Onychodus sigmoides " 



Machseracanthus major " 



M. peracutus " 



M. sulcatus " 



Rhynchodus pangeus " 



K. secans " 



E. crassus " 



Asterosteus stenocephalus " 



Acanthaspis armatus " 



Acantholepia pustulosus " 



Of these, the first two are the most common and conspicuous, and will 

 be recognized from a fe.w words of popular description by all who have 

 seen collections of fossils taken from the Sandusky limestone. 



