Palcoutology of the Cincinnati Group. 179 



wrinkles; upper surface, carrying the calices, gently convex, 

 and without any monticules; calices polygonal, sub-equal, 

 occasionally collected into maculoe ; no interstitial cells ; 

 spiniform corallites situated at the angles of junction of the 

 cells ; corallites directed at right angles to the base, thin 

 walled at first, but becoming thickened ; tubes crossed by a 

 moderate number of complete, horizontal tabulae, frequently 

 placed at corresponding levels in contiguous tubes. (Cat. 

 Foss. Cin. Gr. (name only). Nicholson, Quart. Jour. Geol. 

 Soc, Lond., vol. 30, 1874, p. 511, as Chcctetcs discoideus ; 

 Genus Montic, 1881, p. 193). 



Locality. — Cincinnati, O., near Toronto, Canada ; in Wiscon- 

 sin, etc. 



Remarks. — This species is readily recognized by the disc- 

 like form of the corallum, with the under surface concen- 

 trically striated, and the upper one w'ith tubes of a uniform 

 size and without monticules. 



6. — M. NEWBERRVi Nicholson, 1875. 



Corallum in the form of a thin, sub-circular or semi-circular 

 expansion, 10 lines to one inch or more in diameter, and ^'^ of 

 an inch thick ; generally free, but perhaps occasionally para- 

 sitic, and with a basal epithecal membrane; surface smooth, 

 but with groups of corallites larger than the average, and 

 forming low, inconspicuous elevations; calices polygonal, 

 thin-walled, and interstitial cells observable in well-preserved 

 specimens ; in cross section the corallites are oval, touching 

 each other at some points, the interstices filled^with numerous 

 small and variously -shaped corallites; tabulae of the large 

 corallites imperfect, forming a series of vesicles on one side 

 of the tube, the other being open and without them ; small 

 corallites with closely set, straight tabulae. (Pal. of Ohio, 

 vol. 2, 1875, p. 212, as Chcctetcs newberryi ; Genus Montic, 

 1881, p. 212). {Aspidopora parasitica Ulrich, 14th Ann. Rept. 

 Minn. Geol. and Nat. Hist. Survej', 1886, p. 90. Prasopora 

 contigua Ulrich. Ibid, p. 87). 



Locality. — Cincinnati, O., and in Minnesota. 



Remarks. — This species, while similar to the preceding, can 

 be readily separated from it by the well-marked groups of 



