236 
PALAEONTOLOGY 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. 
Ceramopora imbricella. 
NOT FIGURED. 
Lichenalia ( Ceramopora) imbricella. Hall. Report of State Geologist for 1883, p. 37. 1884. 
Zoarium consisting of a thin lamellate expansion, attached 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. 
