﻿Bulletin 17 14 



First : The almost universal prevalence of Orthis teshtdinaria , 

 Rafinesquina alternata, Plectambonites sericeus,, Orthoceratites, 

 Asaphus platycephalus and Calymene senaria throughout the 

 formation. 



Second : The much greater number of forms found in the 

 Black River zones, and in general, also in the lower zones than 

 in those above. 



Third : The presence of crinoids ; Prasapora, Rhynchotrema 

 inczquivalvis ; and Trinucleus concentricus , principally in the lower 

 parts. 



The fourth, fifth and sixth are not quoted, as they are not 

 pertinent to the present paper. 



Prosser and Cumings* measured the section very accurately 

 and corrected the statigraphy of Mr. White's paper. They 

 made no attempt to divide the section faunally, however. 



The Section. 



A. 1-20 of field notes. Lower part of A 1 of Prosser and 

 Cumings. Zone of Triplecia extans. 



Lowest layers exposed in the section. It extends from water 

 level at the Narrows to the footpath. Fine grained, dark gray 

 limestone, in layers from one to eleven inches thick, alternating 

 with thin, shaly layers. About eight and one-half feet below 

 the path is a very fossiliferous layer, from which good specimens 

 of Trocholites, Murchisonia, Triplecia, and the two common 

 trilobites may be obtained. 15 ft. 10 in. = 15 ft. 10 in. 



Lingida sp., r, Calymene senaria, c, 



Trematis terminalis, r, Ceraurus pleurexa?ithemus , rr, 



Dalmanella testudinaria, r, Leperditia sp. , r, 



Rafinesquina alternata, c, Stictopora sp. , rr, 



Plectambonites sericeus, rr, Monticulipora lycoperdon, c, 



Triplecia extans, r, Ctenodonta levata, r, 



Zygospira recurvirostris, r, Trocholites ammonius, r. 



Bellerophon bilobatus, r, Orthoceras sps., c, 



Murchisonia gracilis, rr, Endoceras sp., r, 



Asaphus platycephalus, r, Crinoid columns, c. 



* Lower Silurian Sections. Fifteenth Annual Report of the New York 

 State Geologist. 1895. Vol. I, p. 619. 



