Geology and Mineralogy. 253 



interesting point in paleontological research. But if they" mi- 

 grated, where did the forms come from originally ? As far as may 

 he determined from the character and thickness of the rock de- 

 posits now remaining from that time, the land of the Clinton sea 

 seems to have been nearest southeastern Pennsylvania, and thence 

 to have curved around toward the Atlantic, both on the north 

 and the south, perhaps more rapidly toward the north. This 

 land, judging from the contributions it made to sedimentary 

 strata, from the Clinton to the Upper Carboniferous periods must 

 have had decidedly continental proportions. To our knowledge 

 the sea deposits along the northwest of this paleozoic continent, at 

 present represented in part at least by the deposits of Anticosti, 

 was the only place showing comparatively no paleontological 

 break between the Lower Silurian and the Clinton I'ocks and very 

 likely was one of the sources from which certain of the Clinton 

 fossils of the anticlinal came. The distribution of such forms as 

 Pleurotomaria var. occidens, Holopea obsoleta var. elevata and 

 Spirifera rostellum make it probable that such continuous breed- 

 ing places for species existed also along the southwestern side of 

 the paleozoic continent. 



No doubt intermediate localities occurred of which we have no 

 record and the position of which we cannot at present reconstruct. 

 The very great range of many of the Clinton fossils, from Anti- 

 costi and New York to Alabama, while at a short distance off the 

 line toward the westward they are absent for a time, or even per- 

 manently, make it probable that the species migrated north and 

 south, comparatively freely in the shallower waters off the shore 

 of the paleozoic continent, but that they found some physical ob- 

 stacle in reaching the anticlinal. This obstacle was not land, 

 since the well-borings of Ohio show that the Clinton is continuous 

 between these two regions. Perhaps it was deep water which 

 made the chances for migration over the short distance from the 

 anticlinal to the Alleghany axis less satisfactory than the oppor- 

 tunities for migration for hundreds of miles along the western 

 border of the old paleozoic continent. 



That the anticlinal during the Clinton period was near land at 

 least, seems probable from the occurrence of conglomerate in the 

 southern exposures of the Clinton in Ohio. But what formations 

 were then exposed, and where, seems not so certain. The pebbles 

 from the Clinton of Ohio near Belfast in Highland county do not 

 present recognizable remains in any of the specimens seen by us, 

 nor is their lithological character such as to present positive evi- 

 dence of any except their sedimentary origin. The cement bind- 

 ing the pebbles together contains very fresh specimens of Cyclo- 

 nema btlix and well-preserved specimens of the so-called corals 

 mentioned by the Ohio Geological Survey, but which are chiefly 

 species of branched forms of Plilodictyw: Ptilodictya famelicus, 

 Ptilodictya rudis, Stictopora similis, Phcenopora Jimbriata and 

 Phwnopora magna. Cyathophyllum celator var. Daytonensis 

 was also found. Single specimens of Orthis biforata, with two 



