128 NEW YORK STATE MUSEUM 



The Old Red Sandstone. The conception of these beds as to 

 origin is now rather definitely formulated. Through years of waver- 

 ing interpretation we have reached a point at which we may concede 

 the essential continental origin of most of the deposits which may 

 be fairly embraced under the designation above employed. The 

 force and proof of this conception is largely due to the effective 

 work of Professor Barrell, who has attacked the problem from an 

 angle new to the usual approach. The Catskill formation of the 

 Appalachians and the Oneonta sandstone which lies at or is con- 

 tinuous with its western base, are, according to this interpretation, 

 the outwash or delta plains composed of the debris of the more 

 easterly lying mountainous lands, now either completely lost beneath 

 the eastern sea or represented only by their metamorphosed roots. 



I think that for the interpretation of these great delta plains 

 fringing the interior sea of the Upper Devonic, too little emphasis 

 has been laid on the tremendous mid-Devonic mountain making all 

 through the northern Caledonid Appalachians — a time of orogenic 

 revolution which greately overpassed in energy that of any other 

 period in the history of the mountains. With the opening of late 

 Devonic time, all through this region there were the newly made 

 mountains rising to fresh heights and inviting the most vigorous 

 attack of meteoric waters ; inviting, too, as a natural consequence, 

 the formation of such tremendous plains of continental debris all 

 along the shore lines. 



There must have been on the now buried eastern shores of Appa- 

 lachia, deltas of similar origin and extent to those we now know on 

 the western shores. While the general proposition is a closed one 

 and we may find satisfying explanations of all the phenomena pre- 

 sented by the accumulation of continental material on the edges of a 

 marine basin, with all necessary accompanying phenomena of inter- 

 digitation of deposits, local repulse and invasion of marine faunas, 

 etc., there still remain some open questions as to the scope of the 

 continental factor, in time, and as to -its exclusiveness in effect. 



Does the Catskill formation, in its typical development in the 

 Catskill mountains of New York, represent exclusively Devonic 

 sedimentation, or does it transcend the Devonic boundary? As- 

 sumption commonly favors the former, but there are outside evi- 

 dences that indicate the latter presumption, drawn from a con- 

 sideration of the 'Bona venture conglomerate, 



Bonaventure conglomerate. This mantle of sandstone and 

 Conglomerate sheets the present coasts of the northern Mari- 

 time Provinces of Appalachia, seldom extending inland in its region 



