G. D. Walcott — The Taconic System of Emmons. 233 



is on the western crest of Clarksburg Mountain, northeast of 

 Williamstown, Mass. It is one of Dr. Emmons's typical local- 

 ities, and it has also been examined by Professor C. H. Hitch- 

 cock, who, in speaking of the relations of the quartzite to the 

 Green Mountain gneiss, says : 



" 3. Still more decisive is the fact that the lowest layer of 

 the quartzite has been derived from the ruins of the gneiss. 

 This stratum is a conglomerate, containing many pebbles of a 

 peculiar blue quartz, and has been observed at Clarksburg, 

 Mass., Sunderland, East Wallingford, Bipton, and in Lauzon 

 conglomerate, at Bristol. (The Geology of Northern New Eng- 

 land : royal Ito, p. 2, 1870). 



When making observations during the summer of 1887 on 

 Clarksburg Mountain, I found* the unconformity between the 

 quartzite and gneiss to be well marked. The lower layers of the 

 quartzite series contain shales and thin beds of conglomerate, 

 and there are no passage beds between the quartzite series and 

 the gneiss in the localities where the bedding of the gneiss and 

 quartzite series appears to be conformable. In accordance with 

 this, the unconformity has been represented in the section. 



The quartzite, including certain minor beds of schistose shale, 

 conglomerate and limestone, I will call terrane number one. 



Terrane Wo. 1.— Professor James D. Dana, in describing 

 the Quartzite series, in a paper on the Geology of Vermont 

 and Berkshire, says " Associated with the limestone belt and 

 following mainly its eastern border there is a quartzyte series, 

 consisting in Vermont of quartzyte and crystalline slate or schist 

 (hydromica slate, sometimes chlorite slate), and rising at inter- 

 vals into mountain ridges. This quartzyte formation commences 

 just abreast of the northern limit of the 'Eolian limestone' in 

 Vermont : and it follows it southward through Massachusetts, 

 and into Connecticut, being, throughout, its close attendant " 

 (Amer. Jour. Sci., vol. xiii, p. 38, 1877). And on p. 204 : "(4) 

 The age of the Quartzyte formation, and its relation in position 

 to the adjoining limestone. — The quartzyte formation includes, 

 as has been explained, strata of quartzyte and schists — some- 

 times one predominating, and sometimes the other. The special 

 age of the formation is in doubt, equally with that of the eastern 

 limestones. There may be quartzytes of different, periods of 

 the Lower Silurian : and so with the schists. The question of 

 age can be positively answered only by the discovery of decisive 

 fossils in the quartzyte of Vermont : and so many imperfect 

 forms have already been brought to light (besides the unsatis- 

 factory worm-burrows, and Fucoids or worm-tracks) that we feel 

 sure the future will clear away the doubts." 



Professor Dana considers that the evidence proves the ex- 

 istence of a limestone beneath the quartzite, in some sections, 



