416 Dodge and Beecher — Occurrence of Upper 



Along the north shore of the Thoroughfare, east of the vil- 

 lage, are red shales that closely resemble those north of Ames's 

 Knob, J 7. Here also the dip is southward. They overlie a 

 mass of diabase, which is vesicular in its upper (southern) 

 portion. A layer of light colored porphyry lies among the 

 shales and extends westward along the shore between the 

 wharves at the village. Farther west, near the ferry landing, 

 are fragmental rocks with an ash-like cement, which must over- 

 lie the red shales. In this vicinity are dykes of diabase and of 

 light colored porphyry showing flow structure parallel to its 

 walls. 



The northern part of Vinal Haven, excepting Calderwood's 

 Neck, is made up largely of felsophyre (laminated, some- 

 times spherulitic) and felsophyre-breccia, with porphyrite 

 and diabase. The southern part, including the greater por- 

 tion of the area of the island, is mainly occupied by granite. 

 Along the northwestern side of Seal Cove, which opens into 

 the Thoroughfare, is a limited region of altered schists, into 

 which are intruded dykes from the granite near the head of 

 the Cove. The schists strike 1ST. 20°-40° E., and dip north- 

 westward, 40°-55°. 



The presence at North Haven of a familiar species of Mono- 

 graptus gives an interesting item of information in regard to 

 the geographical distribution of Upper Silurian graptolites in 

 America, of which but little is yet known. Graptolites have 

 been reported as occurring at a few Upper Silurian localities 

 in New Brunswick, Nova Scotia and Newfoundland. Repts. 

 Canada Geol. Surv., 1885, pp. 14, 15 G; 1874-5, p. 10, 1885, 

 p. 52 E ; 1886, pp. 43, 46 P ; Geology of Newfoundland (1871 

 Rept.), p. 31. They were mentioned as occurring at Anticosti 

 at a somewhat high level in the (Middle Silurian) Anticosti 

 Group, Rept, 1853-7, p. 253, 1863, p. 302, but were not in- 

 cluded by Billings in his first published list, or in his catalogue 

 of 1866. w. w. d. 



II. 



The paleontological evidence furnished by the specimens 

 from North Haven apparently does not admit of a distinct 

 subdivision of the rock series into recognized periods. A large 

 proportion of the species clearly points to a correlation with 

 the Niagara of New York, and to this period they are here 

 referred. The presence of quite a number of characteristic 

 Clinton species is a disturbing element in any attempt to draw 

 exact parallelisms with the New York subdivisions of the 

 Upper Silurian. From present data, however, it seems justi- 

 fiable to consider the fossiliferous rocks at North Haven as 

 representing a faunal equivalent to the Clinton and Niagara, 



