466 C. H. HITCHCOCK — AMMONOOSUC DISTRICT, NEW HAMPSHIRE 



blende schist. Sections to the north of Fitch hill would illustrate the 

 presence of other igneous rocks. 



These eruptive rocks, being misunderstood in our early studies, caused 

 us to announce what now seems to be very singular conclusions. Our 

 teachers had taught us to believe in their sedimentary origin. Diorites, 

 diabases, and protogenes were simply altered sediments, and were rele- 

 gated to a different class from the truly igneous masses of the same 

 names, with the convenient prefix of meta. Thus a metadiorite was not 

 to be thought of as being an igneous mass, but a metamorphic schist, 

 having the same minerals with its congener. The presence of foliated 

 planes indicated stratification. The influence of this theory seems to 

 have affected the opinions of Doctor Hawes, whom I employed to write 

 up the lithology of the New Hampshire rocks. My advisers, however, 

 disagreed as to the age of these schists, the one class referring them to 

 the Huronian (the original " Quebec group "), and the other to the 

 higher place indicated by the fossils. I now regard the foliated schist 

 as truly igneous. 



It should be remarked that I am not speaking of the green schists 

 extending through the middle part of Vermont between Canada and 

 Massachusetts, but only of the Connecticut Valley range, which widens 

 very much in the northern part of New Hampshire; and it is an inter- 

 esting circumstance that when one wishes to understand the petrography 

 Of these crystallines he must consult the descriptions of the original 

 Huronian rocks about lake Superior. It was perfectly natural for those 

 who were observing the similarity between the eastern and western 

 schists to believe them to be of the same age. Possibly the tables may 

 be turned some day, and a portion of the schists now called Algonkian 

 may be proved to be Paleozoic. 



Little need be said of an outcrop of augen-gneiss or porphyritic granite 

 in the corners of the towns of Littleton, Bethlehem, Whitefield, and 

 Dalton. It is the most northern area of that rock in the state, and there 

 are no facts at present known to make clear its relation to the modern 

 groups. It does not seem to have sent out branches into the adjacent 

 formations. 



A somewhat triangular area of granite, both massive and foliated, lies 

 westerly from the porphyritic variety. It contains occasionally inclu- 

 sions of schist in its western part. It is doubtful whether it extends 

 easterly into Bethlehem, as represented on the state map. It is more 

 closely allied to the chloritic granites on Parker brook than anything else. 



The most extensive granitic area is that called in the report Bethlehem 

 gneiss or protogene. A characteristic variety, identical with the " epidotic 

 mica gneiss " from Lebanon, is number 38 of the educational series of 



