1866. ] the Western Himalaya and Afghan Mountains. 119 
irregularly in the rock, or as smaller geodes mixed among long cylindrical and 
twisted branches of quartz running through the mass. (See figs. 1, la. plat. X.) 
I must confess, I had some difficulty in understanding these branches; they look 
precisely like the arms of a canal or like small rhizomes, and they sometimes 
have the form of worm-burrows ; they begin with thick branches or trunks about 
the sizeof the finger and throw out smaller twigs; they are often 6 or 8 inches 
long, and are cut obliquely by both stratification and cleavage, I have come to 
the conclusion, after examining a great many of these cylinders, that they are 
gas-vents, similar to the amygdala in origin, the imprisoned gas, in its efforts 
to rcach the surface, having had sufficient streneth to force a long passage 
though the viscid paste.* Dip 55° to 60° ...............0c0see cee about 600 ft. 
5. Amygdaloidal greenstone, graduating to trachyte; with innumerable 
small geodes, rounded and pressed together. The greenstone becomes rough 
and gritty and passes into a trachyte, it is much less amygdaloidal; and on 
the other hand, where the rock is excessively amygdaloidal, the paste is a 
dark brownish black rock, which is cleaved into well defined slabs, and breaks 
easily into prismatic fragments. This bed forms a depression between harder 
layers. The stratification is easily seen by the several courses of the rock 
superposed one on the other; but of course it is not seen in the thickness of 
GAO, COWES dos 'candedsuntagg euvoreawandadaanpucncsehinn eA abana eT oN Soa eeaeante cLexe ano, 0.8 tr 
6. Pale bluish greenstone, hard, compact, with conchoidal fracture ; it is 
closely spotted with irregular dots of hornblende. At the base of each compact 
layer, there is a margin 1 orl} foot thick and very amygdaloidal, the 
geodes being filled with quartz. It is a very hard stratum ... about 150 ft. 
7. Closely set amygdaloid. The paste is a greenish felspar, sometimes 
very compact and then dark, and cleaved into slabs half an inch thick , 
sometimes light in shade and with the amygdala rather irregular and nearly 
touching one another. In many specimens, the felspathic paste shows 
a division of the felspar into a bluish or greenish mass and patches of white 
felspar ; but there is no crystallization. Dip 70° nearly due H. The fels- 
pathic paste decays pretty quickly and thus this bed forms a depression 
Dial WS Lav MNCS) 8 coee kage s Ueda ro Ubmera manne te aatnan ecuane center Ane oMer A cB Tn anaRe 50 ft. 
8. This is the stratum on which the celebrated Buddhist ruin is built; it 
is the highest summit of the Tukt-i-Suliman (6263 ft.) It is composed 
of very hard, dark greenstone, with amygdala of white quartz, occurring 
sparingly. Beds of lighter coloured greenstone, with specks and nodules of 
augite are interstratified. A great many well defined long cylinders of quartz, 
either white or black or smoky, such as I have described as gas vents, are 
seen here, This stratum is a hard saddle or ridge; nearly vertical, and 
EMEC ira yay) ede ts fees oa os icn taste tele vaginas iterantemntvuscass |. GOGs 
* T have since read that Dr. MacCulloch observed in Little Cambay, one 
of the Western Islands of Scotland, amygdaloid containing elongated cavities 
similar, | believe, to those which are here described, 
