The Primitive Fishes 267 



shale, Berea grit, and Cuyahoga shale. We need not linger 

 over the dispute as to whether these should be regarded as 

 Lower Carboniferous or Upper Devonian. Shortly the 

 writer would consider that they are probably contemporane- 

 ous below with the Upper Old Red, and above with the 

 Calciferous of Europe. But their mode of origin and the 

 enclosed organic remains deeply concern us. 



Newberry and successors have viewed the Corniferous 

 as a marine series, and it may at once be accepted that the 

 Lower or Columbus Limestone, the Schoharie of authors, 

 is such, for the abundant invertebrate marine fossils fully 

 demonstrate this. It is highly noteworthy however that 

 no fish remains are intermixed with these. But the Dela- 

 ware or Sandusky limestone above, which he considers 

 to have been deposited in some extensive sea, is unquestion- 

 ably freshwater in origin. For in marked contrast to the 

 lower: (a) it is devoid of marine organisms, and though 

 mention is made of occasional Lingula and Discina types 

 these are not normally intrinsic; (b) its lowermost course, 

 the "bone-bed" is a mass of fish remains that all belonged 

 to freshwater species of the period; (c) included in the 

 beds above the last are several forms of tree fern trunks 

 and a Lepidodendron. So we would consider that after 

 deposition of the marine Columbus limestone, some sudden 

 volcanic activity took place, that caused elevation of the 

 land, formation of an extensive lake, destruction of great 

 shoals of freshwater fishes whose soft parts decayed, but 

 whose teeth, spines and plates formed much of the fish 

 or bone bed of two to six inches in thickness. Thereafter 

 continued deposition of freshwater limestone went on, that 

 is largely unfosslliferous, but which encloses tree fern and 

 "Dadoxylon" trunks, parts of Lepidodendron, and occas- 

 ional freshwater fish remains, though no marine inverte- 

 brates. The Marcellus shales seem to form the top of this 

 series. 



Another change in the land and invasion by the sea 

 took place probably gradually, to constitute the "Hamilton" 

 series of rocks. For Newberry says that In "the extreme 

 upper portion of the Sandusky member of the Coniferous 

 group, several characteristic Hamilton fossils are found 



