244 J. D. Dana — Lower Silurian Fossils 



122 pages of the volume), includes in the Lower Taconic, "as 

 developed in Williamstown and Adams ;" the quartzyte ; the 

 schists of the Greylock ridge and others west; the Stockbridge 

 limestone; and, with these, the western or "sparry" limestone 

 and the associated slates ; that is, all the true original Taconic. 

 To the Upper Taconic (p. 49) he refers the black slates and cal- 

 careous beds at Easton, Washington Co., N. Y., which, four or 

 five miles north of Bald Mountain, afforded him the Pri- 

 mordial trilobites ; similar slates and limestones at St. Albans, 

 with some sandstones. He also includes the slates and lime- 

 stone of Poughkeepsie and of the region east of there to 

 Sharon, Connecticut — beds which have recently been proved 

 to contain abundantly, in some localities, Hudson Eiver, Tren- 

 ton and Calciferous fossils (made known from the Poughkeepsie 

 slates first by Mr. Nelson Dale, and from the limestones, by 

 Prof. W. B. Dwight and the author), and which recent dis- 

 coveries of Prof. W. B. Dwight prove to be also in part of 

 Potsdam age, as a paper of his, prepared for the present meet- 

 ing of the Association, announces.* 



Now the larger part of all that has been written on the 

 Taconic question is about the outside rocks — the "Newer Ta- 

 conic." Volumes have been devoted to them which have set- 

 tled nothing. Emmons did not make those Primordial slates 

 Taconic by calling them so, any more than Dr. C. T. Jackson 

 made the Eed sandstone of the Lake Superior region Triassic 

 by calling it so, because the red sandstone of the Connecticut 

 Valley had been determined to be Triassic. Should it be sub- 

 stantiated that the original Taconic of Emmons is in part of 

 Calciferous, Trenton and Hudson River age (that is, Lower Si- 

 lurian), what has been gained from the effort to prove the 

 Primordial slates of Washington County, N. Y., to be not only 

 Taconic in system, but Taconic newer than the original Taconic ? 



We have now unimpeachable evidence — evidence from fos- 

 sils — that those Primordial Trilobite beds are not newer than 

 the typical or original Taconic; that the limestones of the true, 

 original, typical Taconic, on the contrary, are the newer. The 

 Lower Silurian fossils here referred to were found, as has been 

 stated, in the " sparry " or western limestone of the Taconic 

 System — the oldest limestone stratum of the system according 

 to Emmons in 1842. They are from Canaan, New York, the 

 town nest south of New Lebanon. The Boston and Albany 

 railroad, as it crosses the State-line in leaving Massachusetts for 

 Albany enters the town of Canaan and its limestone area; and 

 the fossils have been collected from a cut along the railroad, 

 and from ledges of limestone half a mile south of the road 

 and a mile north of it. 



* Published at p. 125 of this volume. 



