GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 229 



1113 of sienite. The hornblende is in small crystals, disseminated sparsely 

 through crystalline orthoclase. It weathers readily, showing the colora- 

 tion of peroxyd of iron, and rarely manganese. A specimen from the 

 top of Mt. Passaconnaway proves to be of the same character, and one 

 from the northern ridge contains the mineral in profusion. These sum- 

 mits are three and a half miles apart. No one has gone from one to the 

 other, so that it is only by conjecture that we place the intermediate 

 space in the same group. As this variety seems to be intimately con- 

 nected with the Chocorua granite, it is likely that the region east of Mt. 

 Whiteface will be found partially composed of sienite, as appears upon 

 many of our specimens. Those which show hornblende came from the 

 summit of Chocorua, the ravine east of the main peak, and the end of 

 the south-east spur. The colored heliotype of Mt. Chocorua, described 

 upon page 232, will show the location of these parts of the mountain. 

 Other Albany localities are at Ellen's, Champney's, and Swift River falls. 

 Similar specimens came from Camel's Hump, south of Sawyer's river, 

 and from Silver Spring mountain. It is probable that hornblende will 

 be found occasionally disseminated through any mountain mass of the 

 Chocorua granite. 



This is notably true of the ledge called Frankenstein cliff, through 

 which the railroad has cut. There seems to be a mass of this rock 

 slightly inclined north-easterly, starting from some unknown point on 

 the north flank of Mt. Nancy, and extending a little beyond the railroad. 

 Nothing needs to be added to the notice of it upon page 181. 



Sable mountain in Jackson is composed of a sienite abounding in horn- 

 blende, much like that on the north side of Passaconnaway, and is con- 

 nected with porphyry and breccia. Three other localities are Chocorua 

 pond, a mile from Berry's saw-mill, and at Great Hill pond, all in Tam- 

 worth. Near the Crawford house a single large boulder of sienite, very 

 like that from the Chocorua group, has been found, in which Prof. Dana 

 discovered chrysolite. Its source is unknown. It is probable that the 

 same mineral will be found in some one or all of the localities that have 

 been mentioned, as the specimens from all of them are very much alike. 

 We searched the Frankenstein cut carefully for chrysolite, but found 

 none. Boulders of sienite containing chrysolite occur, also, upon Mt. 

 Washington river. 



