135 



Found in the Deniissa bed, at Section .">, Eighteen Mile 

 Creek (common). It is often overgrown with l)i-v()zoa. 

 Also found at Morse Creek. This species is readily recog- 

 nized by its cylindrical corallites, nnmei'ous irregular 

 branches and coarse cysts, which are well shown in cross- 

 section. 



Ceratopora dichotoma. Graban. (Fig. IS.) (1891): 

 Proc. Bost. Soc. Nat. History, Vol. XXVIIL, p. 418. Pis. 

 II. toIY.) 



DistiuLiuishingChar^cters. — Free prostrate habitat ; lower 

 flattened, and upper convex or sloping and carinated sur- 

 faces; abruptly upturned calices; regular dichotomous 

 branching, with branches diverging at right angles; tri- 

 angular cross-section of main tube; circular cross-section of 

 calyx; large inner cavity lined with moderate-sized cysts and 

 trabecule ; wrinkled epitheca . 



Found in the lower Moscow shales, three to five feet above 

 the Encrinal limestone ; also in the Demissa bed, at Section 

 5 ; and in the Lower shales, seven feet below the Encrinal 

 limestone, at Section G; and between nine and twenty-one 

 feet beloAv that bed, at Section 7. 



This species is readily recognized by its regular branches, 

 its flattened lower surface, triangular cross-section, uptui-ned, 

 round calyx, and central carination. The specimens vary 

 greatly in size, those of the Demissa bed being the largest. 

 They are usually found with the calices embedded in the 

 shale, the flat face alone being exposed. 



Gexus TRACHYPORA. E. and H. 



[Ety. : Tvacliys, rough; poros, pore.] 

 (1851: Edwards and Haime, Pol. Foss., d. Terr. Pal., p. :iO.">.) 



Corallum dendroid, with cylindrical stems. The corallites 

 are polygonal, with very thick walls, the calices being 

 rounded and superficially far apart. Mural poi'es few, irreg- 

 ularly distributed; septa represented by row^s of spines; 

 tabulae present at remote intervals. 



