I3O NEW YORK STATE MUSEUM 



of some further examinations, made for the State Museum, of the sections 

 at Rondout and southward into Greene county with the especial aim of 

 elucidating the composition of that element of the Helderbergian group 

 known as the Port Ewen fauna, and though these results have not been 

 put in final form I have availed myself of the author's permission to refer 

 to some of his determinations. More lately the progress of field work has 

 developed a quite novel aspect of the Oriskany fauna in sections at High- 

 land Mills, Orange county, in an area on the east of Skunnemunk mountain 

 where the presence of these rocks had not before been accurately deter- 

 mined. This section with its contents will presently be noticed, but it is 

 desirable just here to summarize our present knowledge of the earlier or 

 Port Ewen fauna. 



Port Ewen beds. To rehearse briefly the history of this stratigraphic 

 unit, these are a series of thin limestones and gray lime shales which, in the 

 Appalachian region of New York and New Jersey, lie immediately on the 

 Becraft limestone, bear the lithic character of the New Scotland lime shale 

 and carry a large percentage of Helderberg fossils. It is a division not recog- 

 nized by the early geologists of New York in their partition of the " Lower 

 Helderberg" and it is entirely absent from the succession west of Schoharie. 

 Its earliest recognition as a distinct unit was by Prof. W. M. Davis who in 

 discussing the structure of the Little Mountains east of the Catskills [Appa- 

 lachia 3. 1882; Am. Jour. Sci. 1883. ser. 3, 26:389] termed these rocks 

 whose position he determined as above the Becraft limestone the " Upper 

 shaly beds" contrasting them in this designation with the " Catskill or Del- 

 thyris shaly limestone " below. Professor Davis did not attempt to delimit 

 the beds and did actually, according to Professor Chadwick, include in his 

 division some part of the " Upper Pentamerus " (Becraft) limestone. In a 

 joint publication with Professor Schuchert [Science. 1899; also in N. Y. 

 State Mus. Mem. 3. 1900] the writer recognized the distinct unit character of 

 these beds and termed them the " Kingston beds," later [Handbook 19, 1903] 

 substituting for this term which proved to have been previously employed by 

 the Canadian geologists for a quite different formation, the name Port Ewen 



