C. D. Waleott — Fauna of the Upper Taconic. 187 



Art. XXII. — Fauna of the " Upper Taconic " of Emmons, in 

 Washington County, N. T. With Plate I. By Charles D. 

 Walcott. 



[Published by permission of the Director of the U. S. Geological Survey.] 



Lsr his second memoir on the " Taconic System,"* Dr. Em- 

 mons described two species of trilobites from the black Taconic 

 slate near Bald Mountain, Washington County, N. Y. ; Atops 

 trilineatus and Elliptocephala asaphoides. Subsequently the 

 black slate was referred to the upper division of the Taconic 

 and with it the contained fossils. It is the fauna of which 

 these two species form a part that is embraced within the title 

 of this paper. 



From the time of the original discovery and description of 

 the fossils by Dr. Emmons, up to the present, no discovery of 

 Cambrian or First Fauna fossils has been reported from Wash- 

 ington County, except in 1886, when the discovery of Cam- 

 brian fossils at Granville was made known. f 



At an horizon in Georgia, Vermont, equivalent to that of the 

 " Upper Taconic " series, fossils were found by Noah Parker, 

 Esq., and given to Bev. Z. Thompson, who sent them to Pro- 

 fessor Hall who, in 1859, described and referred them to the 

 Hudson Biver shales (Twelfth Ann. Bep. State Cab. Nat. 

 Hist., 1859). Subsequently, this reference was changed to the 

 Quebec group (Thirteenth Bep., idem, 1860), by Professor 

 Hall, and in 1861 (Geol. Surv. Canada ; New Species Lower 

 Silurian Fossils, by E. Billings, p. 1, 1861), they were referred 

 to the "Potsdam Group (Primordial Zone)," by Mr. E. Bil- 

 lings. Subsequently Mr. S. W. Ford discovered an equivalent 

 fauna in the vicinity of Troy, N. Y., and concurred with Mr. 

 Billings in referring it to the Lower Potsdam (this Journal 

 III, vol. ii, p. 34, 1871). Afterwards Mr. Ford discovered that 

 the fauna extended farther south and into Columbia County, 

 N. Y. 



In the introduction to Bulletin 30, of the U. S. Geological 

 Survey, I have given a summary of our knowledge of this 

 fauna (Taconic or Middle Cambrian) as known to date of pub- 

 lication (1886), and to that I will now add the results of my 

 study of the fauna of the typical "Upper Taconic" area and 

 section in Washington County, N. Y. 



* Pamphlet. 1844, reprinted in Agric. N. Y., vol. i, pp. 64, 65, 1876. 



f Proc. Amer. Assoc. Adv. Sci., advance sheet, December. 1886; Cambrian 

 Age of the Roofing Slate of Granville. Washington County, N. Y. ; Charles D. 

 Walcott. 



tlna paper read by the writer before the National Academy of Sciences, April 

 22, 1887, the name Taconic is restricted to the Middle Division of the Cambrian. 

 This paper, with map and sections, will be published within a short time. 



