PHYSICAL HISTORY OF NEW HAMPSHIRE. 523 



Dana upon the geology of eastern New England, published in the American Journal 

 of Science, II, vol. L, p. 83, in which he includes the rocks of the White Mountains 

 with a group in Nova Scotia recently investigated by Mr. Murray, and stated to contain 

 "soft bluish-grey mica slates and micaceous limestones, belonging to the Potsdam 

 group ; besides a great mass of whitish granitoid mica slates, whose relation to the 

 Potsdam is still uncertain. To the whole of these we may perhaps give the provisional 

 name of the Terranovan series, in allusion to the name Newfoundland." This series 

 is definitely stated to lie "between the Laurentian and the Quebec group." 



Next, Dr. Hunt describes rocks of similar characters on the St. Croix, N. B., and in 

 Nova Scotia. He says of the latter, "These include mica schists with chiastolite and 

 garnet, and appear identical with those already observed by Dr. Dawson in other parts 

 of Nova Scotia, which I had already recognized as the same with those of the White 

 Mountains, and those of the St. Croix." He says further of the same, "which I 

 believe to belong, like those of the St. Croix and the St. John rivers, to the great 

 Terranovan series. The micaceous and hornblendic schists, with interstratified fine 

 grained white gneisses (locally known as granites) which I have seen in Hallowell, 

 Augusta, Brunswick, and Westbrook, in Maine, appear to belong to the same series, 

 which will also probably include much of the gneiss and mica schist of eastern New 

 England." Of another region he says, in the same letter, "I believe, however, that 

 much of the calcareous mica slate of eastern Vermont will be found to belong to the 

 Terranovan series." 



From these quotations I think it plain that the author is inclined to believe that the 

 rocks of the White Mountains, together with the micaceous staurolitic rocks of eastern 

 Vermont, belong to one system, which is styled the Terranovan. As certainly a part 

 of this is stated to belong to the Potsdam, I should infer that the author believed the 

 Terranovan series to have been deposited about the time of the Potsdam or Cambrian 

 period. 



In 1870, my second annual report (page 26 of this volume) amplifies the definition 

 of the White Mountain series, making it to include everything now referred to the 

 Atlantic system, and, also, the porphyritic granite. The name of Coos group was 

 applied in the second report to a set of rocks along Connecticut river, that had been 

 marked in 1869, upon a published map, as distinct from the White Mountain series. 

 This report was prepared immediately after the reading of Dr. Hunt's letter, referred 

 to above, in manuscript ; and the two documents were printed about the same time. I 

 gave the name under the impression that the group represented by it corresponded 

 to the Terranovan series of Newfoundland, and was nearly of Cambrian age ; but, as 

 distinctly shown in the reports for 1869 and 1870, I separated the Cob's from the White 

 Mountain series, the latter being regarded as pre-Cambrian. 



In 1871, Dr. Hunt delivered a very able and carefully prepared address before the 

 American Association for the Advancement of Science, in which he distinguished 

 between the gneiss of the Adirondacks, the quartzo-feldspathic rocks of central Ver- 

 mont (improperly termed the "Green Mountain series," since the rocks of the Green 



