STRATIGRAPHICAL ELEMENTS: CRYSTALLINES, ETC. 79 



of a hornblende-schist from a plagioclase-augite rock, agreeing stage 

 by stage with those figured and described by Teall from the Scourie 

 dyke. A rock which was manifestly from its structure and composi- 

 tion a massive igneous rock composed of plagioclase, augite, and 

 titaniferous iron ore, has been converted, doubtless by dynamic 

 metamorphism, into a fissile schistose rock composed of hornblende, 

 quartz (possibly also granular secondary felspar), and sphene. 



No. -glv thin dyke Kirpiliyan, Indus river, and No. 8 -f 5 , dyke 

 LaloGulee Indus river. These are both further examples of foliated 

 epidiorites, and indicate an origin similar to that of gf-^-. The former 

 is composed of layers of granular hornblende and quartz with some 

 brown mica and nests of sphene ; the latter is even more pro- 

 nouncedly a hornblende-schist than even -g-f T , and the long prismatic 

 hornblende crystals are frequently broken into jointed lengths. 



No. -jrf -g, 2 miles N. W. of Daree where the Sirun river joins the Dore 

 river. This is a similar schistose epidiorite, but more indistinct and 

 less re-crystallised after crushing. 



A few more examples of these dyke rocks may be given :— No. 

 8 -, occurring in the gneissose-granite -£ mile south by east of the 

 <( D" of Doguh is a noncrystalline rock more nearly resembling the 

 plagioclase-augite rock, or dolerite, No. 6 # ¥ , than anything else ; but 

 it contains, besides the minerals in the latter, a deep clove-brown 

 mineral intimately connected with the titaniferous iron ore and 

 shading off into it. It is slightly pleochroic (brown to violet-brown 

 colours), with strong double refraction, and may be a form of py- 

 roxene. The rock possesses a peculiar striping and Assuring in one 

 direction, and along the lines or fissures there is sometimes a green 

 amorphous mineral. 



No. -gf 4; is simply a coarsely crystalline variety of 5 f T , with por- 

 phyritic idiomorphic plagioclases shewing zones of growth, and with 

 inclusions of jointed rods of apatite and granules of augite. There 

 is a little brown mica also in the slice. In the diagram below (fig. 5) 

 a crystal of plagioclase is shewn with the outer zone not quite sym- 

 metrically disposed around the central one. In the latter darker part 

 the granules of augite are confined. 



( 79 ) 



