SPENCER— VIAGARA FC^SSILS. 605 



mit. Margins of frond rounded, with the surface covered by about 

 nine fenestrules in its breadth, in the branches, and twelve below 

 the bifurcation. Fenestrules subrectangular, and much longer 

 than broad ; and separated by the comparatively stout cellulif- 

 erous portions of the frond, connected by very delicate crossbars. 

 Porous structure not well defined, having been obliterated in the 

 crystallization of the limestone. Length of frond, nine centime- 

 tres, and breadth from 1.5 to 2 millimetres. The general appear- 

 ance is like a bundle of fine tiireads lying close together and con- 

 nected transversely by finer cross-threads. 



Of this beautiful species only one specimen has been obtained, 

 and its general form is quite distinct. 



Fo7'niatio?i and Locality. — This specimen was obtained from the 

 calcaieous beds of the Clinton rocks at Hamilton. 



PoLYPORA (Fenestella?) albionensis, nov. sp. 

 Plate 7. Fig. 5 & 5rt. 



Frond both flabellate and cyathiform on the stone, but always 

 funnel-slniped in growing state. Branches rounded and mostly 

 originating near the base, and dividing but a few times, with 

 slight divergence, and extending to the margin without dichoto- 

 mous terminations. Branches rather farther apart than their 

 thickness, and connected by very slight transverse bars, situated 

 more or less regularly at two or three times as far apart as the 

 branches. Fenestrules oblong-subquadrangular or subrhomboi- 

 dal. Branches circular in growing state, and longitudinally stri- 

 ated with the surface indicating more than two rows of pores 

 imperfectly preserved. 



The branches are about a quarter of a millimetre broad, and 

 separated by rather more than that distance, with cross-bars about 

 one millimetre distant from each other. From the base to the 

 summit of the frond the measurement is two and a half centime- 

 tres, and the diameter of the circular frond double that distance. 



This species closely resembles Polypora inceps^ with branches 

 more slender, and the transverse filaments not expanded at junc- 

 tion with branches, as in that species, producing a somewhat 

 oval fenestrule, whose transverse to longitudinal diameters are as 

 about 4 to 7, while in this species they are as i to 3 or 4. 



Formation and Locality. — This exceedingly beautiful species is 

 found high up in the series of the Niagara formation, in the shaly 



