Maryland Geological Survey 103 



exi^ressed in 183 faunnles." This list contains tlie 12 species given in tlie 

 standard one and tlie following four additional ones : 



13. Liorhynchus laura. 



14. Paracyclas lirata. 



15. Chonetes scitulus. 



16. Stropheodonta perplana. 



These four additional species likewise occur in the Hamilton beds 

 of Maryland. 



The above review of the paleontological evidence shows conclusively the 

 extension of the iN'ew York Hamilton as far southwest in the Appalachian 

 basin as Maryland and the northern jjart of West Virginia. 



Professor Williams after an examination of the preliminary lists from 

 the Hamilton beds of Maryland arrived at essentially the same conclusion 

 which he stated in the following paragraph : 



" In the list furnished me by Professor Prosser there appear 132 

 entries, 91 of which are positive identifications. Among the latter are 

 found all of the dominant species of the Tropidoleptus carinatus fauna, as 

 estimated from the New York statistics. This is sufficient to establish 

 the extension of the Tropidoleptus fauna, in its integrity, as far south in 

 the Appalachian trough as Maryland." ' 



Other facts brought out in this report by Clarke, Swartz, and the 

 writer, apparently show that the Hamilton beds of Maryland are suc- 

 ceeded by deposits and faunas similar to those succeeding the Hamilton 

 of New York and therefore it may be concluded that the deposits of the 

 Hamilton beds from iSTew York to West Virginia were brought to a 

 close at about the same geological time. 



Geological Distribution of Species. 



The geological range in New York and Maryland of the Middle De- 

 vonian species listed in this volume is given in the tables of distribution. 

 The following seven species, viz.: Orthonota undulaia Conrad, Palaeo- 

 neilo cJarkei Prosser, Cijclonema ( ?) inanjJaiulense Prosser, Orthoceras 



' U. S. Geol. Surv., BuH. No. 210, 1903, p. 67. 



