J. D. Dana — Brief history of Taconic ideas. 425 



part of the mica schist and gneiss remained in doubt, as, for 

 example, that of Hoosic Mountain east of North Adams, and 

 that of Mt. Mansfield in the Green Mountains,* not knowing 

 whether to pronounce them of the age of the Taconic Grey- 

 lock schists which they closely resemble, or of that of the 

 schists in the Quartzyte formation, or of Archaean age — think- 

 ing the last the least probable. f 



In 1884 Professor C. H. Hitchcock published an account of 

 new sections made by him across Yermont and New Hamp- 

 shire, sustaining essentially his former conclusions as to the 

 Lower Silurian age of the limestone and slates, making the 

 Eolian limestone Lower Silurian. J 



Other papers, besides those that have been mentioned, ap- 

 peared during the thirty years from 1855 to 1886, but none of 

 importance that were the direct result of investigation of the 

 Taconic region apart from what appeared on Northern Yer- 

 mont and Canada. Articles on the Taconic system by Dr. T. 

 Sterry Hunt have come out from time to time since his first 

 in 1849 giving the views he had adopted ; views that were 

 strongly opposed to Professor Emmons for nearly thirty years, 

 and for the last ten, from 1878 to 1888, as strongly or a 

 little more so, in favor of the Taconic system and in contest 

 with the facts that were fast accumulating against it. As the 

 arguments and conclusions presented were at no time based on 

 his own investigations in the Taconic region there has been no 

 occasion to cite from his papers. 



1887, 1888.— -In 1886 Mr. Charles D. Walcott, the excellent 

 paleontologist of the United States Geological Survey, com- 

 menced the study of the Taconic slates, limestone and quartz- 

 yte of Northern and Southern Yermont and the adjoining 

 counties in New York; and in 1887, he continued his work 

 southward into Williamstown in Massachusetts and to Berlin, 

 southwest of Williamstown, in eastern New York. He added 

 largely to the number of known Cambrian fossils of the 

 Georgia region in Yermont and of Washington County in 

 New York besides studying the stratigraphy ; made many new 

 discoveries of fossils in southern Yermont, finding in the 



*Mt. Mansfield is the only peak of the Green Mountains which I have 

 ascended. 



f The quartzyte regions of (1) Washington, Mass., southeastern Pittsfield and 

 eastern Lenox, (2) the eastern border of Tyringham, Mass., (3) the southern border 

 of Canaan, Ct. adjoining Cornwall, and (4) the northern border of high eastern 

 Sharon, Ct, near Salisbury, where there are quarries, are among the best locali- 

 ties for the study of transitions in the quartzyte toward gneiss ; they were to 

 have been my field of work in 1887, and failed to be so because of my sudden 

 move to the Hawaiian Islands. 



%G. H. Hitchcock, 34 pp. 8vo, with 2 plates, Concord, N. H., 1884. Bull. 

 Ainer. Mus. N. Hist, i, no. 5, p. 155, 1884; a note to the title says, "This article 

 was prepared in 1882." 



