COMPOSITION AND AGE OF SCHISTS 425 



thus evident that, in so far as the Canadian representative is concerned, 

 the above term is not at all applicable. 



The announcement of these results stimulated further study of this 

 same problem within the limits of Vermont. The investigations of Mr 

 G. H. Barker under the directions of the state survey produced similar 

 results. The specimens analyzed came from Roxbury, Pownal, and 

 Middlesex respectively. 



The name " talcose " as applied to the Vermont schists is also an un- 

 warranted term, although it is to be said that talc and talcose lenses are 

 not uncommon within the limits of the schist formation. 



Age of the schists, — As to the age of the schists, various interpretations 

 have been offered. If I am correct in correlating the schists, with which 

 the asbestos-bearing serpentines are associated in Quebec, with the 

 occurrence under consideration, the Vermont series would be regarded 

 by the Canadian geologists as belonging somewhere in the Quebec 

 group. 



The term " Quebec " is applied to a large series of metamorphics, 

 including slates, schists, and serpentine deposits. It is probable that 

 it, in reality, included both Cambrian and pre-Cambrian rocks. More- 

 over, the occurrence of graptolites within the limits of the Quebec group 

 also shows that it includes rocks of Ordovicic age as well. Where in 

 the series the schists and the associated serpentines belong is not yet 

 clear from the evidence at hand. It has been stated by the Canadian 

 Survey that the schists are in all probability Cambric in age. 



The southern extension of the schists, as represented in Old Hampshire 

 county, Massachusetts, and Windham county, Vermont, has been studied 

 in very great detail by Professor Emerson. Using the Vermont geolog- 

 ical map as the basis for comparison, the talcose schists of Vermont are 

 continuous with the Goshen schists of Franklin and Old Hampshire 

 counties. This terrane is considered as Siluric by Emerson. Inasmuch, 

 however, as the United States Geological Survey did not adopt the term 

 " Ordovicic," as suggested by Lapworth, for Lower Silurian in the no- 

 menclature of geologic folios until this year, it should be noted that the 

 term "Silurian " as used by Emerson probably includes rocks of Ordo- 

 vicic or possibly earlier age. If this interpretation be correct, it is clear 

 that the Quebec group of the Canadian Survey and the Silurian as used 

 by Emerson may overlap or include one or more formations of one and 

 the same age — that is, the upper members of the former may be syn- 

 chronous with the lower members of the latter ; but to what extent they 

 may be chronologically parts of the same formation can not be deter- 

 mined with the data at hand. Such evidence as can be obtained from 



