FOSSILS OF THE CLINTON GROUP. 535 



Cyrtoceras {Glyptoceras) subcompressum, Beecher. 



(Plate 32, Figs. 7 a, b, c, d ; Fig. 3 of p. ate on page 536,) 



The type specimen came from Brown's Quarry (Pal. N. Y., Vol. 7, p. 

 35). Other specimens were collected at the same locality (Proc. Bost. 

 Soc. Nat. Hist., 1889 ; Am. Geol., Sept., 1893). The shell increased quite 

 rapidly in size and was strongly bent, but not coiled as at first supposed. 

 The outer or convexly bent side of the shell was flattened, giving rise to 

 angulate outlines on either , side where this outer side merged into the 

 lateral faces of the shell. The inner side of the shell shows the greater 

 convexity in cross-sections. A fuller discussion is provided in the pub- 

 lications above mentioned. 



Cyrtoceras {Glyptoceras} Eatonense, (Cla3^pole) Foerste. 



(Figs. 1 a, b, c, 2, of plate on page 536.) 



At the base of the limestone at Huffman's Quarry, in a companion 

 piece to the "Orthoceras block," was found a specimen of this genus 

 whose concave septa can readily be seen at the fractured ends of the shell, 

 above and below, but the siphuncle is not exposed. At the smaller ends 

 its diameters are 60 mm. and 53 mm., and here the specimen has a sort 

 of transversely quadrangular appearance in spite of its general rounded 

 form, due probably in part to compression. Towards the upper 

 end the shell, although the fragment is only 45 mm. long, is seen to in- 

 crease very rapidly in size. The surface of the shell is well preserved. 

 It is covered by a regularly arranged series of markings, crossing each 

 other in diagonal rows, being larger on the outer curve of the shell. 

 Each marking is bounded beneath by a concave raised more prominent 

 ridge, above which lies a moderately concave or depressed region trav- 

 ersed by ridges slightly less prominent, which are also concavely curved, 

 following the outline of the defining ridge. Owing to the arrange- 

 ment of these figures in diagonal rows and the interference of newly 

 added figures with the upper margins of the older ones, a sort of imbri- 

 cated appearance is produced, which, were it not for the additional orna- 

 mentation caused by the parallel curved lines above described, might be 

 likened to the imbrication of leaf scars in the case of Lepidodendra. 

 The width of these figures is 6 mm. on the inner side and 8 

 mm. towards the outer curve ot the shell. On closer examination 

 it may be seen that the larger ridges, defining the bases of the figures 

 or scars, are formed by the deflection and massing together of the 

 minor parallel ridges where these pass over the defining or limiting 

 borders of the figures. The peculiar structure produced is therefore 

 only an aberrant form of the transversely striated type of ornamentation. 



