FORMATIONS OF THE SKUNNEMUNK MOUNTAIN REGION 49 



and the Shawangunk formations in this cut shows quite clearly 

 that the High Falls shale follows the Shawangunk without break.. 



The passage from the Shawangunk (=Green Pond) conglomer- 

 ate to the High Falls (=Longwood) shale is thus expressed by 

 Darton 1 : " They [=High Falls] are also everywhere intimately 

 associated with, and grade into the Green Pond conglomerate."' 

 Again [p. 384] : " The quartzites grade upward into the Long- 

 wood red shales, and the intergrading is exposed at a number of 

 points along the west slope of Green Pond mountain and in New- 

 York. On the northwestern slope of Pine hill, beds of passage 

 are finely exposed, and the red shale and red quartzite are inter- 

 laminated for a thickness of several feet." Also [p. 391] : " The 

 Longwood shales are not known to overlap, for they merge into* 

 the upper part of the Green Pond rocks in all the exposure." 

 Reference already has been made to the transition of the Shawan- 

 gunk and the Longw r ood as stated by Kummel and Weller. 



The following is the section as shown in the east cut near 

 Cornwall station : 



Feet 

 DEVON I C 



1 Coeymans limestone 40 



UPPER SILURIC 



2 Manlius limestone 7 



3 Rondout waterlime 13 



4 Cobleskill and Decker Ferry limestones 35 



T ' ( Binnewater quartzite 



5 Longwood -I TT . , „ „ : , 

 s ( High Palls shale 



6 Shawangunk conglomerate 25 



120 



Thickness of the Upper Siluric rocks 200 



In all the early work which relates to these formations and 

 until very recently bed no. 4 of the above table, when recog- 

 nized at all, has been regarded as Niagaran in age. It is thus 

 easy to see that with this correlation of the Cobleskill the lower 

 beds which are the Longwood and the Shawangunk would natur- 

 ally be correlated -with the Medina and Oneida respectively. In 

 the same manner, assuming the Shawangunk to be equal to the 

 Oneida, it would follow that the Cobleskill and Decker Ferry 

 would be regarded as Niagaran. As we now know, however,, 

 that the Cobleskill is above the Salina and that all the lower 

 formations follow without any break of importance as has been 

 shown by the work of several writers, it follows that the Long- 



iGeol. Soc. Am. Bui. 180.3. 5: 382 



