and Igneous Rocks of Ensay. 87 



At 19 the rocks are again crystalline-granular and of two 

 varieties. One is of finer texture than the other. The 

 coarser-grained variety consists of felspar and quartz in 

 nearly equal amount, with a very little brown magnesia- 

 mica. A marked feature in this rock, as seen in a thin slice, 

 is the angular and eroded appearance of the felspars. Some 

 are mere remains of crystals. The larger individuals, which 

 are also those which are most eroded, have the appearance of 

 orthoclase. They include some small crystals of triclinic 

 felspar. The remainder of the felspars are smaller in size, 

 and are plagioclase. The quartz has not any peculiar 

 features, and in appearance is like that of the intrusive rocks 

 of the district. 



The finer-grained variety, which is much intermixed with 

 the coarser, is a micro-crystalline granular compound of felspar 

 and quartz, with a good deal of brown mica in scattered 

 flakes. The felspars are all in angular fragments, and, to 

 judge from their structure and from their low obscuration 

 angles, one of the more acid of the soda-lime group. They 

 are very clear and unaltered. Besides these, there are other 

 and larger porphyrinic crystals, less numerously compounded 

 than the others, being either Carlsbad twins, or else this 

 combined with a few lamellae according to the Pericline law. 



This rock is traversed by very fine-grained light-coloured 

 veins. I have before said that such veins are commonly 

 to be seen in the Ensay Rocks, more especially the intrusive 

 ones. This sample is composed almost wholly of almost 

 colourless epiclote in characteristic crystals, and also in 

 masses of crystalline grains, the remainder of the mass being 

 made up of quartz. The larger epidote crystals are in the 

 centre of the vein, and the granular mixture of quartz and 

 epidote is at the sides. Isolated epidote crystals occur in 

 the rock bounding the vein. 



These crystalline-granular rocks extend to 21, where 

 is a binary compound of felspar and quartz, which at 20 

 contains portions of contorted schists, together with patches 

 of coarser materials, such as I have described before. 



Beyond this place the rocks to be seen in tracing the 

 Little River up to the contact of the intrusive massive rock, 

 which is near the Ensay homestead, are schists. Some have 

 a massive character, while others are like much-altered 

 phyllites. In order to learn something of the character of 

 these schists, I prepared slices both of the schistose and the 

 massive types. 



