GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 26/ 



tory is removed to its proper place in the Eozoic. 6. There is no cor- 

 respondence between the White Mountain rocks and those of any part 

 of the Devonian formations with which they have been compared, either 

 lithological or stratigraphical. Our predecessors became so enraptured 

 with the "New York system," that all the rocks in the adjacent states 

 were supposed to constitute a part of it. 7. The late satisfactory refer- 

 ence of the altered Quebec group to the Huronian has shed a flood of 

 light upon the age of our rocks, and rendered still more unnecessary the 

 application of extensive and extreme metamorphism to explain the age of 

 the White Mountains. As there seems to be an unreasonable opposition, 

 in some recent publications, to the existence of a Huronian system, I will 

 discuss its claims to recognition in the next chapter. 



Appendix to Chapter III. 



During the preparation and printing of this chapter, great improvements have been 

 effected in the delineation of the topography and the establishment of the nomencla- 

 ture of the White Mountains. The past year has witnessed nearly as great advance in 

 these particulars as the whole accumulated surveys and traditions of previous years had 

 amounted to. All this material has been employed in the preparation of our topo- 

 graphical model of the state, — upon the scale of one mile to an inch horizontally, and 

 one thousand feet to the inch vertically, — designed for exhibition at the Agricultural 

 college, Hanover, and the Normal school, Plymouth. The basis of the model is a con- 

 tour-map, upon the same horizontal scale, showing all the approved and newly-sug- 

 gested names. The attempt is being made to reproduce, by means of a heliotype or 

 photo-lithographic sheet, the effect of this raised map — with what success will appear 

 in the Atlas. As this is the last opportunity we shall have for speaking of the topog- 

 raphy of the White Mountains, I deem it proper to mention here this map-model, and 

 the additional sources from which the information for it has been derived, chiefly dur- 

 ing the year 1875. 



I. The Portland & Ogdensburg Railroad has been completed through the heart of 

 the mountainous district ; and the engineer-in-chief has allowed us to make use of all 

 the data collected by him for the building of the road. Concerning the great value of 

 the excavations to the study of the formations, I have spoken heretofore. 2. Prof. 

 E. C. Pickering, of the Massachusetts Institute of Technology, with several of his 

 students, especially John B. Henck, Jr., spent the summer of 1875 among the moun- 

 tains, and carefully studied their topography. Mr. Henck carried a plane table upon 

 many of the higher summits, and succeeded admirably in locating their positions upon 

 a map. These gentlemen have kindly allowed us the use of all their results, which have 

 seemed to us to exceed in accuracy the work of Prof. G. P. Bond, which had previously 

 been made the basis of our maps. 3. Miscellaneous sources, — as a few observations of 



