242 O. D. Walcott — The Taconic System of Emmons. 



the Hudson Terrane (No. 6), but 1 did not find that the two 

 parts of Terrane No. 5 are a repetition of the same strata ex- 

 cept possibly for a short distance, near the break between them. 

 The upper or eastern portion is formed of green, purple and 

 drab slates, with thin iuterbedded limestones, carrying charac- 

 teristic Middle Cambrian fossils ; the lower and western part 

 consists of dark and drab shales with interbedded sandstones, 

 calcareous sandrock and limestones that contain Middle Cam- 

 brian fossils. About 2,000 feet from the base, the fauna begins 

 to show the presence of the Lower Cambrian or Paradoxides 

 fauna, but not in sufficient force to overbalance the predomin- 

 ating assemblage of Middle Cambrian species. — (See this Jour- 

 nal, vol. xxxiv, p. 188, 1887). Fossils occur more or less abun- 

 dantly at over 100 localities as now known to me within the 

 typical Taconic area, and they are distributed at various hori- 

 zons throughout the 14,000 feet or more of strata referred to 

 this Terrane. 



An examination of the ^sections and the faunas of Terrane 

 No. 1 and Terrane No. 5, shows that the former is stratigraph- 

 ically and faun ally the equivalent of the upper or eastern part 

 of Terrane No. 5, Terrane No. 1 being the sandy deposit of the 

 shore line, and No. 5, t lie off-shore accumulation of finer sediment. 



Terrane No. 5, like No. 1, is referred to the Middle Division 

 of the Cambrian. 



Terrane No. 6. — This is a belt of red, black and green slates, 

 cherts and sandstones faulted in between the two parts of Ter- 

 rane No. 5. The contained graptolites show it to be a portion 

 of the Hudson Terrane. Its distribution and relation to the 

 other terranes is shown on the map and in the section. 



Resume. — I have briefly noticed the strata included within 

 the Taconic area with the exception of the beds west of the 

 great fault line, separating Terrane No. 5 from the recognized 

 strata of the Calciferous-Chazy-Trenton and Hudson terranes. 

 Along the line of the fault, the strata of Terrane No. 5 are 

 usually thrust against, and, sometimes, over and upon, the latter, 

 but in no instance have I been able to find an unconformity by 

 original deposition between the strata of Terrane No. 5 and the 

 strata of any of the superjacent terranes. This will be more fully 

 described later under the head of Comparison and Discussion. 



In the preceding pages, the strata of the Taconic area are 

 grouped under six terranes and identified as follows . 



Terranes Nos. 1 and 5 = Middle Cambrian.* 



Terrane No. 2= Upper Cambrian.* 



Terrane No. 3 = Calciferous, Chazy and Trenton limestones. 



Terranes Nos. 4, and 6 = Hudson shales, sandstones, etc. 

 [To be continued.] 



* For a description of the term Cambrian as used in this paper see this Journal, 

 III, vol. xxxii, pp. 138-157, 1886. 



