ABSTRACTS OF PAPERS 89 



indicated by disconformities. The Tully-Genesee Sea was restricted to central 

 New York, but extended northward over Canada. Appalachia, Atlantica (the 

 Old Red Continent), and Mississippia were the chief continents. The evidence 

 liointing to the gradual southward transgression of the sea over the eroded 

 lands is clear. Three open marine water bodies existed throughout Upper 

 Devonic time, each with their distinctive faunas : (1) The northern, extending 

 from central New York across Ellsmere Land to the Urals; (2) the western or 

 North Pacific, extending across part of Alaska ; (3) the eastern or Atlantic. 

 The latter entered the interior by way of a narrow strait between Appalachia 

 and Atlantica, permitting the periodic invasion of the Atlantic or Tropido- 

 leptus fauna. There may have been a fourth South Pacific water body ex- 

 tending into Nevada, but this is less certain. Three principal river systems 

 are recognized in the lowland of Mississippia. These have furnished the black 

 mud for the black shales which were deposited in embayments of diminished 

 salinity. The eastern or Genesee beds are restricted to New York and the 

 States just south. The base of the black shale of Ohio, Michigan, and Canada 

 is younger than Genesee, as shown by stratigrapliic and paleontologic evidence. 

 The great fish fauna of these shales is shown, by its occurrence and distribu- 

 tion, to be primarily the fauna of these sluggish rivers projected at intervals 

 into the brackish water of the embayments. The land flora of Mississippia 

 is also pre.served in these shales. The rivers of Appalachia and Atlantica also 

 had their fish fauna, but these were of diffei-ent types, their smaller size 

 adapting them to these torrential streams. With them occurred the survivors 

 of the Eurypterids, which also inhabited the rivers of the Paleozoic lands. 

 The flora of Appalachia and Atlantica is likewise largely distinct from that 

 of Mississippia. The deposits made by these rivers were partly preserved as 

 sandy deltas and alluvial fans. 



Presented in al)straet extemporaneonply. 



Discussion 



Prof. C. S. Prosser stated that in his belief the chart by Professor Grabau 

 showed in general the changes in the character of the sediments of the Ohio 

 shale in northern Ohio to the equivalent ones in northwestern Pennsylvania 

 and western New York. 



In Ohio there is a black shale in the Mississippian (called the Sanbury) 

 separated by the Berea grit and Bedford formation from the subjacent Ohio 

 shale. .\s these formations are followed across the Ohio River in Kentucky 

 the Berea and Bedford rapidly thin until when about one-half the distance 

 across the State the Ohio and Sanbury shales are separated by only a few 

 inches of deposits representing the Berea and Bedford. It ai»pears probal)le 

 that fartlier south these two black shales come together and belong in both 

 Devonian and Mississippian age. 



Professor Prosskr called attention to the extension of the Sherburne .sand- 

 stone (<> tlie sandstone to the east in New York than indicated by Professor 

 Gral>an"s diagram. He (Professor Prosser) has Iniced the Sherimrne sand 

 stone from the typical region in tlie Chenango Valley eastward across th»> 

 Unadilla, Su.squelianna, and Schoharie valleys, and then, after the change in 



