240 PALEONTOLOGY OF OHIO. 



Gentjs ACERVULARIA, Schweigger, 1820. 



(Handb. der Naturg., p. 418.) 



ACEEVULARIA PROFUNDA, Hall. 



Acervularia profunda, Hall ; Geology of Iowa, Vol. I., Part II., pL ], figs. 7, 7c. 



Corallum sub-hemispheric, astrseiform, composed of polygonal, closely 

 united, unequally sized corallites, which vary from less than three to as 

 much as five lines in diameter. Outer walls of the corallites thin ; 

 inner calicine wall rarely well defined, the surface sinking, at first gradu- 

 ally and then abruptly, to form the true cup, the diameter of which is 

 always considerable, and varies from one and a half to three lines. The 

 bottom of the true calice is fiat or slightly elevated. The septa are 

 about forty, more or less, in number, for the most part extending into the 

 true calice, slender, and marked with denticulations closely resembling 

 those so characteristic of the genus Heliophyllum. About six of these 

 denticulations in the space of one line. 



Our specimens do not differ in any material respect from those de- 

 scribed by Prof. Hall from the Hamilton formation of Iowa. The species 

 is most nearly allied to A. Davidsoni, Edw. and H., from which it is dis- 

 tinguished by the smaller size of the corallites as a general rule, the 

 greater inequality in the size of the calices, and the greater number and 

 more conspicuous denticulation of the septa. 



Position and hcality : Oorniferous limestone, Sandusky, Ohio. 



Acervularia Davidsoni, Edwards and Haime. 



Acervularia Davidsoni, Edwards and Haime ; Pol. Foss. des Terr. Pal., p. 418, pi. 9, 



figs. 4, 46. 

 Acervularia Davidsoni, Hall; Geology of Iowa, Vol. I., Part II., pi. 1, figs. 8a, 86. 



Coral astrseiform, massive, composed of polygonal, unequally sized 

 corallites, the average ones being half an inch in diameter. The walls 

 of the corallites are slightly undulated or zigzagged, and the interior 

 wall is rarely defined. The septa are usually forty or forty-two, with 

 finely denticulated edges, about six or seven denticulations in the space 

 of one line. 



The only example of this species which I have seen from the State of 

 Ohio is a polished specimen, which does not exhibit the characters of 



