238 STRATIGRAPHICAL GEOLOGY. 



summit. Other specimens from the smnmit contain a smaller number of fragments, 

 conspicuously large crystals of orthoclase, and have a reddish color. 



9. Porphyry — very much like the preceding — with black slaty fragments an inch long. 

 Near the summit. 



ID. Slate breccia from near the slate. Pieces, one fourth to an inch and a half long, 

 of veritable slate, and one white quartz pebble. From eight to ten per cent, of feld- 

 spathic cement. 



II. Fragment of black compact slate ; 12 — of gray quartz ; 13 — white quartz; 14 — 

 reddish compact micaceous feldspar, — all components of the breccia. Other specimens 

 represent genuine porphyries. 



15, 16. Slate. Nos. 9-16 are from the south slope of the mountain. 



17. Breccia, composed chiefly of dark compact feldspar fragments, with about fifteen 

 per cent, of paste. From top of Bartlett mountain. Nos. 18-26 are from the west 

 slope of this spur. 



18. Porphyry, with reddish base ; pieces of dark compact feldspar and quartz crystals 

 in the base. 



19. Gray compact feldspar or porphyry holding numerous minute crystals of quartz. 



20. Porphyry, with reddish-gray, somewhat crystalline base ; quartz crystals abun- 

 dant ; contains an inch fragment of trap-like porphyry, itself carrying feldspar crystals. 



21. Both drab and light gray base, each color carrying small crystals of quartz and 

 feldspar, and bits of dark porphyry. 



22. Like 19. 23. Like 21. 



24. Compact drab-colored feldspar, very like the fragments seen all through the 

 mountain imbedded in the porphyry. 



25. Porphyry, with dun-colored base, minute crystals of quartz, and white, irregular 

 blotches of feldspar from an eighth to one quarter of an inch in length. 



26. Porphyry, with an abundance of dark brown paste, carrying numerous crystals 

 of quartz and minute crystals of orthoclase, and one or two small pieces of compact 

 feldspar. 



27. Albany granite, like No. 6. This ledge is about a mile east of the road from 

 North Conway to Bartlett. 



It is noticeable that the distinctively slate breccia is confined to the 

 proximity of the slate ledges on the two sides of the mountain, while the 

 balance of the dark pieces consists of compact feldspars, a mass of which 

 occurs at No. 24, on the west side. Explorations might discern other 

 areas of it on other surfaces of the mountain. The length of this por- 

 phyritic area is about three miles cast and west — somewhat less north 

 and south. 



