EARLY DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AMERICA I 29 



THE EARLY DEVONIC IN EASTERN NEW YORK 

 When Professor Hall was elaborating the paleontology of the H elder- 

 berg and Oriskany formations, the development of these rocks in the Appa- 

 lachian region of New York south of the Helderberg mountains did not 

 contribute materially to his stores. The outcrops in this region had been 

 delineated with approximate accuracy by Mather, but in all his paleon- 

 tological work in New York Hall seldom got far away from the undisturbed 

 rocks of the central and western districts of the State to which he was 

 early wedded. Work was later done in this Appalachian region by N. H. 

 Darton and by Dr Heinrich Ries. The latter constructed a map and 

 report of Orange county recording interesting data in regard to details of 

 stratigraphy without attempting close analyses on the basis of paleontology. 

 In these instructive but somewhat involved eastern sections entangled in 

 Appalachian folding, the arenaceous deposits of the Lower Devonic have 

 generally passed as " Oriskany " and the calcareous beds beneath as " Lower 

 Helderberg," designations which are no longer accurate or adequate. Since 

 1890 these regions have been given careful study at certain points and the 

 succession of the faunas closely analyzed. The first of these special studies 

 was that of the Oriskany fauna of Becraft mountain, the sole outlier of this 

 stage east of the Hudson river. This was followed in the year 1903 by 

 two important contributions, one by Dr Stuart Weller on the Paleozoic 

 Rocks and Faunas of New Jersey in which he discussed the sections at the 

 entrance of the western or Port Jervis-Otisville branch of the divided 

 paleozoics of eastern New York and those further south in his own state ; 

 another by Prof. Gilbert van Ingen and P. E. Clark on the Disturbed 

 Fossiliferous Rocks in the Vicinity of Rondout, N. Y. [Mus. Bui. 69] in 

 which all the precise determinations were made by Mr van Ingen. In 1904 

 Prof. H. W. Shimer published the paleontology of the section at Port 

 Jervis known as Trilobite mountain [Upper Siluric and Lower Devonic 

 Faunas of Trilobite Mountain, Orange County, N. Y. ; Mus. Bui. 80]. 



Prof. George H. Chadwick has recently brought together the results 



