Paleoulology of the Cincinnati Group. 187 



to ail inch above the base ; sometimes two elevations are 

 present: calices thin-walled, polygonal, nearly equal in size; 

 scattered over the surface are clusters of slightly larger cells, 

 either even with the surface or raised slightly above it ; inter- 

 stitial cells none ; tabulae numerous, complete, well developed 

 throughout the entire length of the corallum. (Genus Montic, 

 1S81, p. 190.) 



Locality. — Cincinnati, Ohio. 



Remarks. — This is one of the numerous perplexing forms 

 which, while externally similar to others, differs materially in 

 internal structure. It is one of the forms that has been called 

 petropolitaniis. 



var. wELCHi James, 1882. 



This variety has the same general mode of growth as the 

 typical form ; the monticules are much more pronounced, and 

 the central portions are occupied by from four to ten or more 

 small pores, the larger calices surrounding or being mingled 

 with these ; maculae sometimes form conspicuous monti- 

 cules, irregularly arranged and from one to two lines apart ; 

 interstitial cells rarely found scattered among the calices cover- 

 ing the general surface; one peculiar feature is to be found in 

 certain projections, either straight or branching, which spring 

 from the upper surface of the corallum ; internal structure 

 similar to type form. (Af. zcr/r/// James. The Paleontologist, 

 No. 6, Sept. 12, 1882, p. 50.) 



Locality. — Cincinnati, Ohio. 



Remarks. — In the original description it is stated that this 

 may be only a variet}', as it is here considered. Two points 

 of difference are noticed, one in the presence of a few inter- 

 stitial corallites and the other in the monticules. These are 

 scarcely sufficient to warrant specific rank. The largest 

 example observed was three inches in diameter. Broken off 

 projections present various forms, being cylindrical, lobate, 

 flattened or irregular in outline. 



15. — M. WHiTEAVEsri Nicholson, i88r. 



Corallum discoid when }oung, liemispheric when adult, 

 often with wide margins; varying in size from one-half inch 



