April, 1917J Silurian Fossils from Ohio 201 



septa extend about half way from the wall of the corallum toward 

 the central vesicular mass (Figs. 2 E, F); in others, they are shorter 

 (Fig. 2 D). The larger and shorter septa are connected laterally 

 by lainellose structures traversed by pores similar to those traversing 

 the septa. These lamellose structures evidently correspond to the 

 dissepiments of other corals. 



In some specimens, the proximal edges of the shorter septa appear 

 united to one side of one of the adjacent longer septa, usually the one 

 nearer the cardinal side (Fig. 2F). Between the proximal edges of the 

 shorter lamellae and the central vesicular mass, the number of dis- 

 sepiments connecting the sides of the longer septa usually is compara- 

 tively small. 



The pores traversing the central vesicular mass frequently equal 

 a quarter of a millimeter in diameter. Pores of equally large dimensions 

 have been noticed also traversing some of the septa, but the pores vary 

 greatly in size, and some of them scarcely equal a twelfth of a millimeter 

 in diameter. 



Calostylis parvula has been found so far only in the upper 

 part of the Laurel limestone in the Reinheimer quarry, at New 

 Paris, Ohio. Here it is associated with Pisocrinus gemmiformis, 

 Stephanocrinus osgoodensis, Heliolites subtubidatus, and Atrypa 

 reticularis. 



Since the Reinheimer quarry section is the most western one 

 at which all of the Silurian strata occurring north of the Ordo- 

 vician area in southwestern Ohio have been identified, and 

 since this identification presents some difficulties, the following 

 data may prove of some interest. The section is given in 

 descending order: 



Cedarville dolomite. 



Porous dolomite, massive 6 ft. 



Thinner bedded dolomite 1 ft. 3 in. 



More massive dolomite 2 ft. 



Porous massive dolomite, containing Pentameriis oblongus and Phanerotrema 

 occidens 17 ft. 6 in. 



Springfield dolomite. 



Rock resembling Dayton limestone, with Pentameriis oblongus common 



within 6 inches of the top 5 ft. 6 in. 



Rock resembling overlying layers, but very cherty 7 in. 



Euphemia dolomite. 



Rock blotchy and porous, weathering darker. The blotches are 2 to 3 



inches wide 2 ft. 



Transition rock, with white blotches, but not porous 8 in. 



Laurel limestone. 



Rock resembling Dayton limestone, free of chert 8 ft. 4 in. 



Very cherty white limestone, with Pisocrinus gemmiformis, Stephanocrinus 



osgoodensis, and Calostylis parvula near top 16 ft. 9 in. 



Base of Reinheimer quarry. Underlying strata are exposed along ditch 



leading west from cjuarry. 



