264 (Ringneberg on the Niagara Shales. 
From these the plates gradually diminish in size, but increase 
in number, covering the convex and expanded azygous side. 
Dome high, nearly as large as the calyx, lobed, and termi- 
nating in a long proboscis either rising from the central part of 
dome or recumbent. 
Surface of the plates more or less covered with radiating 
ridges and nodes. 
Type Siphonoa-inus tiobilis Hall, described in the 20th Rep. 
N. Y. Mus. Nat. Hist., p. 373. under the name of Glyptocrhucs 
nobilis., and illustrated on plate 10, figs. 9 and 10. 
Another species Sipho7wcrinus artnosus McChesney, w^as 
described, in 1861, in Netv Palccozoic JFossils^^. 95, under the 
name of Eiicalyptocrimis arniostts^ and redescribed and illus- 
trated by Hall under the name of Glyptocrinus armosus^ in 20th 
Rep. N. Y. Mus. Nat. Hist., p. 373, pi. 10, fig. 11. 
THE NIAGARA SHALES OF WESTERN NEW YORK; A 
STUDY OF THE ORIGIN OF THEIR SUB-DIVISIONS 
AND THEIR FAUNiE. 
BY EUGENE N. S. RINGUEBEKG, M. D. 
A few introductory remarks on the stratum immediately un- 
derlying these shales will here be proper. This is the Niag- 
ara Transition group described in 1881.^ It represents the 
period of introduction of many of the species heretofore con- 
sidered as having their inception in the shales, and reveals the 
cause of their introduction. It also forms the connecting link 
between the Clinton limestones beneath, and the formation now 
in question, and explains in large part the comparatively abrupt 
faunal changes which took place at the time of its deposition. 
The jViagara Transition gronp. Since writing the above 
mentioned paper I have noted this formation further east at the 
town of Middleport and as far west as the Niagara gorge, along 
1 The Evolution of forms from the Clinton to the Niagara groups, by 
Eugene N. S. Ringueberg, American Naturalist, 1882, p. 711. 
