190 R. Pumpelly—Paragenesis of Copper 
grained varieties small jet black crystals apparently of augite 
or ernest are occasionally visible. The accessory mine 
ed, many or all of which are probably products of the 
i nan of the iene constituents, are : 
A brick-red foliaceous ee earit had rubellan, occurring as very minute specks 
some fine-grained v it lends a soft = nk -brown appearance to the 
weathered surface, and ai nie s the interio! 
Specular-iron in minute rh seco ation aes ee in the coarser-grained vari- 
eties. 
Calcite in seams, and more frequently in grains and amygdules, especially in the 
f 
amygdaloidal portion of the beds. 
Epidote rarely crystallized; most common in the amygdaloidal 1 serienien fre- 
que : : q 
which occurs in joey and seams, and also as an indurating medium near 
the hanging wall of many beds. : 
ee: in supa ules sai seams, mostly confined to the amygdaloidal portion of 
beds. ‘4 
A inte te mineral, soft, compact, amorphous, greenish- oto sometimes altered 
to oe ee in grains from pin-head to walnut 
A yellowish-green soft earthy mineral, ws ipassid a green cities 
Tauncene and leovbandie in seams and amygdules. 
Analcite in amygdule: 
esse in small c ee and mers in amygdaloidal cavities. 
Nati @ copper sometimes in fine im regnations in the fine-grained rock, Page in thin 
shoots | in scene geen oe chiefly i m the amygdules, masses, shee 
ich form the metalliferous deposits in the rE where it 
en with native saver 
onally a 
Datholite 1 massive in the amygdaloidal portion of some a and also in small 
aggregations of microscopical crystals in the same position! 
_ We have iba cones several recent analyses of different 
and ical vari of these rocks, made by Mr. Thomas 
Macfarlane.* 
Of one of the coarser-grained varieties which forms vey 
thick bits several hundred feet west of the Quincy “vel 
Mr. Macfarlane says: “It is gene 24 a compound nature, 
but all its constituent minerals are not large enough to be 
ree! determined. Conspicuotis’ among them is a dark 
oritic mineral, the grains of which vary from the 
Sviallbat size to one-fourth of an inch in diameter. In the lattet 
case they are irregularly shaped, ites on angles, but t 
are never quite round or amygdalo at They frequet Z 
consist in the center of dark green ae The mineral ® 
in seams and impregnations, ee nearly always ass quarts 
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* taapia mee Report of Progress, 1863-1866, p. 149. 
