GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 211 



The mineral labradorite was found at Waterville, among the mountains, 

 the first of any locality in New Hampshire. The history of its discovery, 

 and the diverse opinions expressed concerning the rocks, especially by 

 Professors Dana and Hunt, have been already stated in Volume I, page 

 37, et scg., so that we may confine our descriptions at this time to notic- 

 ing the occurrence of the rocks in nature, with whatever light may be 

 derived from the controversies respecting them. The first two areas 

 mentioned occupy the south and north flanks of the mass of mountains 

 in Waterville called Tripyramid. 



Southern Area of Labradorite in Waterville. 



In the east part of Waterville three pyramidal peaks attract the atten- 

 tion of observers, from whichever side they are seen, A fourth makes 

 its appearance when the pyramid is viewed attentively. Mr. Morse's pro- 

 files, taken from Mts. Chocorua, Pequawket, Tremont, etc., exhibit well 

 the shape of the mass ; and the topographical aspects are represented, 

 also, upon the special White Mountain map. Tripyramid is washed on 

 the west and south by the head waters of Mad river, and on the north 

 and east by the tributaries of Swift river, notably Sabba Day brook. 

 Bond figures the peaks without names, but with the altitudes from south 

 to north of 4100, 4100, 4200, and 4000 feet respectively, with a course of 

 about N. 10° W. Guyot mentions but one altitude — taken by a pocket- 

 level — of 4086 feet. Upon his map, published in 1 860 from observations 

 made six or eight years previously, Guyot calls the mountain Tripyramid. 

 The Grafton County map, published also in 1 860, gives the name of Pas- 

 saconnaway to the same elevations, and the first publications relating to 

 its geology, by Prof. Perkins and myself, used the latter name. Only this 

 last summer I ascertained definitely that Messrs. Greeley and Mason first 

 proposed to call these peaks Passaconnaway in i860, without knowing of 

 Guyot's suggestion. In our present report the name Passaconnaway is 

 applied to a peak south-easterly from Tripyramid in Waterville, called 

 North Whiteface by Guyot; and later authors seem to approve of this 

 nomenclature, so that it will be retained by us henceforth. These expla- 

 nations will prevent any misunderstanding hereafter as to the peaks called 

 by us Tripyramid and Passaconnaway. 



The notable storm, ending October 4, 1 869, gave rise to a remarkable 



