VERMONT AND WESTERN MASSACHUSETTS 



449 



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

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

 . ... As regards the mica-schists with staurolite, 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, 

 iu the latter region are clearly pre-Cambrlan. I have, moreover, brought to- 

 getlier the evidence of observers in other parts of North America, in. Great 

 Liitaiii, in continen.tal Europe, and in Australia, showing that similar eiyslal- 

 liue scliists, holding these same minerals, always occupy, in these regions, 

 a similar geological hori/on. Prof. Dana hereupon iu(purcs whether any 

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

 certain geological })enod. I answer, that in oi)position to these facts, it has 

 not yet been jiroved that tliey belong to any later geological period than tlie 

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

 as I have dime, that we cau ever hope to deterndue the ueoloudcal value of 

 these ndneral fossils." 



D — ^-a 



Regarding tho exiHteiice of staurolite, etc., as a criterion of geologi- 

 cal age, Dr. Hunt wrote, iu 1878 : 



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

 Btaurolite, cyanite and andalusite, as exclusively characteristic of tiui Montal- 

 ban, a proposition nowltere maintaintMl by the wi'iter, since, altlioug]) they 

 have not been found iu the oldest terranes, tliese mineral species have long 

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

 Rocks, p. 211.) 



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

 remarks given above, luilcss bo intended to hold that statmilite, 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) nmdc in his Address the " White Mountains (Montalban) 

 a newer sei-ies tlian the Green IMountain rocks " (Hurouiau), It does 

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

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



lows : — 



"Mr. Hunt denies that he niM-kes, in his Address, ' the cry^^talliuo schists of 

 the White Mountii.ins a newer series than the Green ]\[ouiUaiii I'ocks ' — 1 liad 

 read ou pages 29 and 33 of the Address ai)proving announcements that I\bic- 

 iarhmo had made the crystalline rocks of the Green Mountains Jliwonian ; 

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

 series is largf^ly deveh)ped hi Newfoundhuul, and that this fact had led lum 



VOL. VII, —NO. U. 20 



