144 PROCEEDINGS OP THE ACADEMY OP [1884. 



NEW FOSSILS FROM THE FOUR GROUPS OF THE NIAGARA PERIOD OF 

 WESTERN NEW YORK. 



by eugfne n. s. eingueberg. 



Medina Group. 

 Sphirophyton arohimedes (n. sp.). PL II, fig. 1. 



Frond large, thick ; growing in loose spirals that gradually 

 decrease in size from below upwards ; about two coils occur in 

 the space of the diameter. 



Surface on both sides crossed by broad, irregular, gently 

 undulose, wavy plications, which radiate from the centre out 

 towards the obtuse rounded margins in subspiral curves, which 

 traverse about one-fourth of the coil, following the general 

 spiral growth, which is sinistral. 



This fucoid is specially remarkable for its thickness and loose 

 spiral growth. It differs from those figured by Hall by growing 

 in decreasing spirals instead of expanding from below up. 



From the upper friable bands of the Medina sandstone at 

 Lockport. 



Clinton Group. 



TRIACRINUS (n. gen.). 



Calyx symmetrical, subelongate, ovoid to pyriform. 



Basals five, arranged in a bilaterally symmetrical series, the 

 median of which is placed to the right of the anal, and is pen- 

 tagonal ; the two next on either side are low quadrangular, and 

 the outer adjoining two, which are wider than the others, are pen- 

 tagonal and have their superior apices directed away from each 

 other. 



The second ring is tripartite and comprised of the large anal 

 and the lower elongated and expanded portion of the two lateral 

 anterior radials. 



Anal very large, forming nearly one-third of the circumference 

 of the calyx ; equilaterally heptagonal ; it rests on one of the 

 quadrangular radials and laterally against the sloping sides of 

 two adjacent pentangular ones. 



The third or true radial ring is equally quinquepartite and has 

 with the second ring — which is really but a modified portion of 

 the third — a bilateral symmetry, but differing from that of the 



