236 PALEONTOLOGY OF NEW YORK. 



and are more distant from each other : from C. imbricella in having the cells 

 less oblique, less distinctly arranged in alternating and imbricating order, the 

 maculae more distant and destitute of cell apertures. 



Formation and locality. Hamilton group, Western New York. 



Cekamopora imbbicella. 



NOT FIODRED. 



Lichcnalia (Ceramopora) imbricella. Hall. Report of State Geologist for 1883, p. 37. 1884. 



ZoARiDM consisting of a thin lamellate expansion, attsiched by the center of the 

 under surface to foreign bodies, epitheca thin, with concentric undulations, 

 and comparatively strong concentric, rounded striae. Cells tubular, arising ob- 

 liquely from the epitheca, gradually enlarging. Cell apertures very oblique, 

 sometimes rectangular to the surface, broadly oval or circular, sometimes 

 having an arched or triangular appearance, diameter about .40 mm., dis- 

 posed in diagonally intersecting lines, regularly alternating and imbricating ; 

 upper portion of cell walls exposed for .50 to .66 mm., and having along the 

 middle a comparatively strong carina. Surface marked by slightly elevated 

 monticules, the centers of which are distant from each other from 6 to 

 7 mm. The apertures on the monticules are usually slightly larger than the 

 others, and the cell wall is exposed for 1 mm. or more ; they have some- 

 times an indistinct radiation, but usually the same general direction as those 

 on other portions of the frond. 



This species resembles C. ? (Lichenalia) foliacea, but may be distinguished 

 by having the cells more oblique to the surface, the upper portion of the 

 cell walls more exposed, the maculae elevated and entirely covered by cell 

 apertures, which do not radiate from the center : from Lichenalia pyriformis it 

 differs as follows ; the cells regularly enlarge to the aperture, and are without 

 denticulated processes : from L. alternata it is distinguished by its smaller and 

 more nearly circular apertures ; in that species they are elongate-oval. 



Formation and locality. Hamilton group, near Alden, Erie county, N. Y. 



