VERMONT AND WESTERN MASSACHUSETTS. 449 



New England crystalline rocks, as it is called by Professor Dana, so far as it is 

 ray own, is limited to my ufHrmation that they are all of pre-Cambrian age. 

 .... As regards the mica-schists with staiirulite, cyanite, andalusite and 

 garnet, I have in my address pointed out the fact that they appear to belong to 

 a great series of rocks, very constant in character, which have a continuous 

 outcrop from the Hudson River to the St. John, a distance of 500 miles, and, 

 in the latter region are clearly pre-Cambriau. I have, moreover, brought to- 

 gether the evidence of observers in other jmrts of North America, in Great 

 Britain, in continental Europe, and in Australia, showing that similar crystal- 

 line schists, holding these same minerals, always occupy, in these regions, 

 a similar geological horizon. Prof. Dana hereupon inquires whether any 

 one has yet proved that these mineral characters are restricted to rocks of a 

 certain geological period. I answer, that in opposition to these facts, it has 

 not yet been proved that tkey belong to any later geological period than the 

 one already indicated ; and that it is only by bringing together observations, 

 as T have done, that we can ever hope to determine the geological value of 

 these mineral fossils." 



Regarding the existence of staurolito, etc., as a criterion of geologi- 

 cal age. Dr. Hunt wrote, in 1878 : — 



" It is by a misconception that some have been led to regard the presence of 

 staurolite, cyanite and andalusite, as exclusively characteristic of the Montal- 

 ban, a proposition nowhere maintained by the writer, since, although they 

 have not been found in the oldest terranes, these mineral species have long 

 been known to occur, in many localities, in the Taconian schists." (Azoic 

 Pvocks, p. 211.) 



We do not understand what Dr. Hunt did mean, in 1872, in his 

 remarks given above, unless he intended to hold that staurolite, cyanite, 

 and andalusite were characteristic of Montalban schists ; neither does it 

 seem to us that any other construction is possible. It is to be further 

 noticed that, in his reply to Professor Dana above quoted, Dr. Hunt 

 emphatically denied the correctness of Professor Dana's statement, that 

 he (Hunt) made in his Address the "White Mountains (Montalban) 

 a newer series than the Green Mountain rocks " (Huronian). It does 

 not appear to have occurred to Professor Dana that this denial was 

 not made in good faith by Dr. Hunt, since he (Dana) replied as fol- 

 lows : — 



" Mr. Hunt denies that he makes, in his Address, ' the crystalline schists of 

 the White Mountains a newer series than the Green Mountain rocks ' — I had 

 rea<l on pages 29 and 33 of the Address approving announcements that :\Iac- 

 larlane had made the crystalline rocks of the Green Mountains Hurnuiau ; 

 and then, on page 34 of the Address, the statement that the White Mountain 

 series is largely developed in Newfoundland, and that this fact had led him 



VOL. VII NO. U. 29 



