316 C. D. Walcott — The Taconic System of Emmons. 



conic ;" also, that it is the arenaceous deposit that accumulated 

 along the pre-Paleozoic shore while the siliceous, argillaceous 

 and calcareous muds, now forming the " Upper Taconic," were 

 being deposited to a greater depth off the immediate shore 

 line. This entirely negatives the conclusion of Dr. Emmons, 

 that the "Upper Taconic" slates were superjacent to the 

 "Lower Taconic" rocks. 



2. The second' formation, the " Stock- 

 bridge limestone," has afforded fossils 



• that prove.it to be the equivalent of the 

 Trenton, Chazy and Calciferous lime- 

 stones of the Lower Silurian of the New 

 York section, and it is not, as claimed 

 by Dr. Emmons, a peculiar pre-Silurian 

 deposit of limestone. 



3. Conformably resting upon the 

 " Stockbridge limestone" the " Talcose 

 slates" (Terr. No. 4) occupy the strati- 

 graphic position of the Hudson Terrane, 

 in the New York section, and a species 

 of graptolite, abundant in the Hudson 

 Terrane, occurs in the " Talcose slates " 

 near Hoosick, N. Y. 



We have next to consider the rela- 

 tions of the " Upper Taconic" slates to 

 the superjacent Silurian formations and 

 the value of the stratigraphic and pale- 

 ontologic identifications of' the age of the 

 " Upper Taconic." 



In the first published section* of the 

 " Taconic System," the " Shales of the 

 Champlain Group" are represented as 

 resting unconformably against, and on, 

 the Taconic slates. This is repeated in 

 the section published in 1844-47.f 

 These two sections are largely theoretic, 

 but, on page 89 (loc. cit.), Dr. Emmons 

 gives a section of Bald Mountain, in 

 the town of Greenwich, Washington 

 County, 1ST. Y., which is here reproduced 

 (fig. 11). ._ 



This section is intended to show the 

 unconformity between the Taconic slates, 

 b, b\ b'' ', and the Calciferous formations, 

 d, c and d', it being assumed by Dr. 

 Emmons that the slates, b. b' and b". 



* Geol. N. T.; Rep. Second Geol. Dist, p. 145, fig. 46. 1842. 

 f Agric. N. T., vol. i, p. 63, fig. 1, 1847. 



