Il6 NEW YORK STATE MUSEUM 



York record is imperfect, both in sedimentation and in life; not 

 from extensive erosive destruction, but from minor diastrophies 

 and unfavorable geography. But the same growth of knowledge 

 has fortified the standard New York Devonic section as thoroughly 

 complete and indicial, lacking in no essential detail in quality of 

 development, presenting in some degree at least all the phases of 

 the system as exhibited in its transcontinental development, how- 

 ever these phases may vary in magnitude from great to small. 



It is within reason and accuracy, then, to say that not in Devon- 

 shire nor in the Rhineland, not in the Urals nor in Siberia, not 

 on the Bosporus or in South Africa, not in the basin of the Amazon, 

 of the La Plata or in the Andean Cordilleras, is the full and 

 variant succession of Devonic events so well recorded or at least 

 so clearly and simply presented, and perhaps so fully known, as 

 in New York. Upon this stage the successive scenes of the great 

 drama were set without serious intermission and the players made 

 their exits and their entrances till the curtain fell. . 



The panorama of development in Devonic geography and life 

 here set forth has justified the arduous years of labor spent upon 

 its elucidation. The efforts made to turn upon the New York record 

 every ray of light that any other part of the earth could contribute 

 have served to establish its integrity and to fortify it as the ideal 

 monument of Devonic history; while, in its turn, it has responded 

 like a Rosetta Stone, in helping to decipher the significance of the 

 fragmentary and less known. Its problems are as many as the grow- 

 ing host of students which later years have drawn to their solution, 

 but there are some of general import bearing broadly upon the 

 interpretation of the system as a whole to which it is here designed 

 to make special allusion. 



I THE LOWER BOUNDARY 



The limestone faunas. The problem of the base of the system 

 never became a matter of serious question until brought into the 

 foreground by Professor Kayser's proposition that the limestone 

 faunas of the northern Hartz and the F, G, H stages of Bohemia, 

 which had passed as Upper Siluric, were logically and more ap- 

 propriately to be regarded as a deeper water fades of the early 

 Devonic seas. In presenting the broader correlations which resulted 

 from his discussion of the general theme, Kavser included with the 

 equivalents of these misinterpreted lower Devonic lime faunas, 

 the "Lower Helderberg " formation of New York and its various 

 subdivisions. Just here was the entering wedge for the American 

 problem. Soon Tschernyschew in the Urals, Barrois in the Astnrias 



