Report of tee State Geologist. 87 



Ptilopora nodosa. 



Ptilopora nodosa, Hall. Trans. Albany Institute, vol. x, p. 196, 1881. 



Keport of State Geologist for 1883, p. 59, 1884. 

 " " " Palaeontology of New York, vol. vi, p. 285, pi. Ixvi, 



fig. 25, 1887. 



* * * -x- * ** * * 



This species may be distinguished from P. striata by the more 

 slender, non-tapering midrib, more distant lateral branches, and 

 the presence of a line of nodes along the middle of the cel- 

 luliferous face of the midrib and branches ; from P. infreque^is it 

 may be distinguished by the more frequent lateral branches ; in 

 that species the intervals between the branches being equal to 

 three or four times the width of the branches. 



Formation and locality. — Hamilton group, railroad cutting, two 

 and one-half miles east of Alden station, Erie county, N. T. 



