274 Pirsson and Washington — Geology of Red Hill, N. H. 



Or ... 36-14 



Ab... 37-20 = — =- — = — = L Persalane 



Fern 4-66 1 ' 



An... 2-78 



T 1 S-77 



Ne... 13-92 ^r = z =0-24 = 6, Russare 



F 76-12 ' 



So ... 4-S5 Sal = 94-89 



Di ... 1-08 — *— - — ?— = — -=21-5 = l, Miaskase 



CaO' 10 



01 ... 1-05 K o 0' 65 „. , 



Mt... 1-62 N^O' = l40 = " 46 = 4 ' aSe 



II 0-91 Fem. = 4-66 



Rest . 0-94 



Total, 100-49 



Ilomblende-tracho-umptehose ( Umptekite). 



In ascending Red Hill by the route usually followed, the 

 road to the Home farm and path thence to the north peak, 

 when the farmhouse has been left behind, one soon begins to 

 ascend over crumbling ledges of the syenite, and, towards the 

 top, exposures of the rock are frequent. This portion of the 

 massif, the upper part of the north peak, consists of a some- 

 what different type of rock from that just described, and it 

 appears to be the one investigated by Bayley, so far as one can 

 judge from his description and from the localities where he 

 states his specimens were collected. His account is so com- 

 plete that the study of the material affords nothing new that is 

 of especial value, particularly as the rock is made up of the 

 same minerals described above, and differs from it only in their 

 relative proportion and in its texture. Only these characters 

 then need to be considered here and its position in the quan- 

 titative classification. 



Mode. — With respect to the minerals there is a larger quan- 

 tity of femic and alferric minerals present, as may be seen in 

 the specimens and as shown in the calculated norm. While 

 hornblende is still by far the predominant one, there appears 

 to be a somewhat greater amount of biotite. A pale green 

 nonpleochroic pyroxene is found in some sections, in others 

 segirite. Bayley* speaks of a bright green hornblende, which 

 has not been observed by the writer ; he does not mention 

 segirite, which is widely distributed in the Red Hill rocks, 

 though nowhere abundant, but the doubt which arises as to 

 whether the aegirite could have been confused with horn- 

 blende must be yielded in favor of so close and accurate an 

 observer. 



*Loc. cit., page 246. 



