406 THE JOURNAL OF GEOLOGY. 



bed of massive quartzite might not be affected by minor folds is 

 recognized, as it is well known to be among the most resistent 

 rocks. The series below, however, possesses quartzites still more 

 massive and flinty, rocks which have been involved in close flex- 

 ures as sharp as those in fissile associated beds. Through Mas- 

 sachusetts and southern Vermont the quartzite is remarkable 

 for its persistence. The series immediately beneath is extremely 

 variable in character and thickness due to original deposition 

 and to the metamorphism that it has suffered. This series may 

 be wanting, as on Clarksburg Mountain and at North Bennington, 

 Vermont, where the quartzite lies unconformably upon crystalline 

 gneisses. 



In Walcott's hypothetical section across this continent, the 

 Cambrian ocean is represented as sending a long arm up the 

 Rutland Valley not covering the Green Mountains or the Adi- 

 rondacks. Careful search through the Green Mountains proper 

 has not resulted in finding any traces of the quartzite, there is no 

 evidence that it once mantled over the range, although it is not 

 unlikely that the Plymouth Valley was once occupied by Cam- 

 brian waters. There are abundant occurrences, however, of the 

 lower series in the heart of the range, where many of the high- 

 est peaks are capped by one member or another. There is strati- 

 graphical and microscopical evidence that this series has under- 

 gone repeated disturbances ; the quartzite exhibits but one. 

 This fact cannot be used legitimately as evidence of disparity in 

 age, as it is probable that the thick bed of quartzite stood 

 like a bulwark among more variable, less-resistant strata, not 

 taking part in and not recording orographic movements unless 

 of extreme intensity. It should not fail to be stated that in 

 many localities the quartzite lies directly upon fissile mica schist, 

 the upper member of the series below in apparent conformity 

 therewith, and the difficulty of referring the schist to the Lower 

 Cambrian or the Algonkianis apparent. I am disposed to believe 

 it of the latter age and to make it the uppermost member of an 

 upper series with the metamorphic conglomerate delimiting the 

 series below. There are many reasons for this view, some of 



