236 C. D. Waleott — The Taconic System of Emmons. 



i 

 the mountain, reaching into the valley north of North Adams- 

 Mass. On the western summit of the mountain, toward Will 

 iamstown, the quartzite series come in unconformable contact 

 with the pre-Cambrian gneiss ; and fragments of a trilobite, 

 apparently the genus Olenellus, were found about one hundred 

 feet above the contact. 



As a result of the discovery of fossils, in situ, in the quartz- 

 ite east of Bennington, the fossiliferous bowlders are given a 

 value, as they were undoubtedly derived from the quartzite for- 

 mation, and were distributed in the valley to the west during Qua- 

 ternary time and even at the present by floods occurring in the 

 gorges and valleys that cut through the quartzite. It is now 

 a question of search to trace the fossiliferous horizon in the 

 quartzite from Starksboro, to Bennington, Yt. and to Dutchess 

 County, N. T., where Dr. Mather considered the " Quartzite " 

 metamorphosed Potsdam sandstone, and he so called the com- 

 pact sandstone of Stissing Mountain, in the northeastern part 

 of Dutchess County, N. Y. (Geol. N. Y. ; First Geol. Dist., p. 

 418, 1843). During the field season of 1886, I had the oppor- 

 tunity of visiting the Stissing Mountain sandstone locality, in 

 company with Professor W. B. Dwight, and we found Hyoli- 

 thettus micans in the limestone layers, resting immediately on 

 the sandstone ; and the heads of Olenellus Thompsoni in the 

 sandstone, fifty feet or more below the limestone. Hyolithellus 

 micans is known only in the Georgia terrane of New York, 

 Yermont and Canada. A species of Triplesia is associated with 

 the Olenellus at Stissing Mountain, but it has little value in 

 the correlation of strata. 



If we now turn to the geologic map, we find that all the 

 localities I have mentioned are on the line of outcrop of the 

 quartzite (Terr. No. 1). 



Mesume.—The stratigraphy shows the quartzite series (Terr. 

 No. 1) to be the oldest of the Paleozoic sediments known 

 on the eastern side of the Taconic area, and the contained 

 fauna correlates it with the middle division of the Cambrian, 

 but not as low in position as the fauna of the lower strata of 

 the Georgia Terrane. (See Terr. No. 5.) 



Terrane No. 2. — Dr. Emmons, when describing the sections 

 of Graylock (Am. Geol., vol. i, pt. 2, p. 17, paragraph 16), 

 states that the " rock overlying the quartzite is again talcose 

 slate, siliceous at its base, but purely a talcose slate as a mass 

 and which requires no further description. It is between 400 

 and 500 feet thick and extends up the limestone which con- 

 stitutes the seventh member of the Lower Taconic system." 

 It is this belt of shales that I have numbered 2 on the sections : 

 and it is assumed to represent, at this point, the Potsdam sand- 

 stone of the western side of the Champlain basin. This ter 



