EARLY DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AMERICA 2 I I 



complanata, while in C h. dawsoni such fasciculation is very much 

 less pronounced in adult growth. 



There is little difference in character of exterior between this species 

 and C h. jervisensis Schuchert from the Oriskany beds in the Nearpass 

 quarry section near Port Jervis, N, Y., but the latter is uniformly of small size 

 and is very abundant at this locality. Mr Schuchert, who has described this 

 Port Jervis shell and has compared it with one of similar dimensions from 

 the Helderbergian fauna of St Helen's Island near Montreal (C h. mon- 

 trealensis)' states that the critical difference in these two small species is 

 in the fasciculation of the striae in the latter and their subequal size in the 

 former. If we briefly analyze this distinction among known species of the 

 genus it is found that in the earliest form, Ch. helderbergiae H. & C, 

 of the New Scotland beds, the lineation is subequal, in the latest C h. 

 re vers a Whitf. of the Onondaga limestone, the fasciculation is most pro- 

 nounced from early stages on. Chonostrophia montrealensis, 

 C h. j er vise nsis, C h. complanata and C h. dawsoni are successive 

 variant expressions of exterior. Fasciculation of surface striae is a second- 

 ary condition and the retention of the more primitive expression as in 

 Ch. jervisensis and C h. dawsoni indicates delay in the assumption 

 of mature features. We shall be justified in concluding that Ch. jervi- 

 sensis and C h. dawsoni represent one style of variation, while the 

 group consisting of Ch. montrealensis, Ch. helderbergiae and 

 Ch. complanata are likewise different variants of the same specific type. 



In State Museum memoir 3 the writer was disposed to unite C h. com- 

 planata and C h. dawsoni but with present evidence, while the species 

 are very closely alike, it seems quite possible to distinguish them [see 

 description of C h. dawsoni, p. 241]. 



Localities. Chonostrophia complanata has been obtained from 

 Dolbel brook and Shiphead near the base of limestone no. 8 and in the 

 higher beds at Little Gaspe. It is not uncommon at Perce and occurs very 

 rarely in the Gaspe sandstones. 



Anoplia nucleata Hall 



Plate 41, figures 15-17 



Leptaena ? n u cleata Hall. Palaeontology of New York. 1859. 3:419,1)1.94, 



fig. la-d 

 Anoplia nucleata Hall & Clarke. Palaeontology of New York. 1892. v. 8, 



pt I, pi. 15, fig. 17, 18; pi. 20, fig. 14-17 

 Anoplia nucleata Clarke. New York State Mus. Mem. 3. 1900. p. 51, pi. 7, 



fig. 14 



This diminutive species, common in the Oriskany and known in the 

 Helderbergian of New York, occurs occasionally, the specimens showing 



' Amer. Geol. 1901. 27:250. 



