﻿GEOLOGY OF THOUSAND ISLANDS REGION 77 



formation, and much complicates the successful working out of the 

 section. 



Extent of the Pamelia formation. In a preliminary paper pub- 

 lished some months ago, based on the field work up to the close of 

 1907, the writer attempted to predict the extent of the Pamelia 

 formation in New York and adjacent Ontario, in so far as the 

 published literature warranted. The result of the field work of 

 1908 necessitates some modification of the statements there made, 

 all of which prove to have been too moderate. 1 



The study of the formation on the Clayton sheet, and the work 

 about Kingston, show that the formation does not thin as rapidly 

 in those directions as had been supposed. About Kingston the 

 formation has much prominence and considerable thickness, much 

 of the upper division, and the basal sandstones being well repre- 

 sented. The upper dove limestones of the New York section are 

 here capped by thin bedded, earthy, shaly layers, weathering yel- 

 low, above which the Lowville comes in, with its basal conglom- 

 erate. The division plane between the two formations is therefore 

 much easier of recognition than on the New York side. 



Up the Black river valley we measured sections at Lowville and 

 on Roaring creek, near Martinsburg, the latter a wonderfully fine, 

 continuous section from the Precambric up into the Trenton. We 

 were at the time ignorant of the fact that Prof. W. J. Miller was 

 engaged in the areal mapping of the Port Leyden sheet, on which 

 this section occurs. That being the case its detailed exposition is 

 left for him. 2 Suffice it to state that it shows a thickness of 72 

 f eet, 6 inches of Pamelia, overlaid by 54 feet, 7 inches of Lowville ; 

 and that, of the Pamelia, the lower 19 feet is of sandy beds, fol- 

 lowed by 8 feet of blackish limestone with abundant marine fossils, 

 the remainder showing alternating beds with the characters of the 

 upper division though the upper dove beds are lacking. Miller 

 reports that the formation is traceable to the south line of the Port 

 Leyden sheet, but does not appear beyond. This is, however, well 

 toward the upper end of the Black river valley, and gives the 

 formation in New York ,a measured length of outcrop of 70 miles, 

 from southeast to northwest. The Kingston occurrence adds 15 

 miles more to this distance, and it is quite probable that the forma- 

 tion may run west for some miles across the Ontarian peninsula. 



Our work was done, and a preliminary paper published, while in 

 ignorance of the existence of a paper by Dr Ells upon the adjacent 

 Canadian district. This paper, as the quotation which follows will 



1 Geol. Soc. Am. Bui. 19:165-71. 



2 N. Y. State Mus. Bui. 135, p. 22, 23. 



