xlii Report of the Miner alogical Survey [No. 126*. 



in one instance of limited occurrence have I observed it of reddish hue. 

 The quartz is most commonly white and semi-transparent, occasion- 

 ally grey ; the mica is of all shades, varying from silver white to a deep 

 brownish black ; some specimens contain both extremes of colour. 



80. There are three distinct types of structure in this gneiss, two of 

 which are well separated, both in appearance and position. The lami- 

 nar which is often contorted, the granular, 31 in which the laminar 

 structure is often obscure ; and what may be termed the glandular. The 

 first two appear to pass into each other, and to be irregularly mixed 

 together, but the third preserves a great uniformity of appearance over 

 a considerable tract. It has really the laminar structure as strongly 

 marked as the first, but it is well distinguished from it by the imbed- 

 ded lenticular, or round nodules of felspar which it contains, and which 

 give it a most peculiar appearance. The lamina? are bent round these 

 nodules, which have a foliated structure, and are sometimes disposed in 

 two layers ; the line of junction, which coincides with the axis of the 

 nodule being so faint as only to be perceptible by the varying reflection 

 of light from the two parts. There is very little doubt but this line of 

 junction coincides with one of the faces of composition of the mineral, 

 but I have not yet established this point to my satisfaction. 



81. The dip of this rock appears involved in some obscurity; along 

 this line, at least it presents some anomalies, the explanation of which I 

 have yet to learn. This may be, nay doubtless is, partly owing to the 

 frequent concealment of the rock beneath the coating of debris, leaving 

 us in these cases to form our judgment from the configuration of the 

 mountains, with reference to the sides of slope and precipice. Even 

 this test sometimes fails, either from the great accumulation of debris 

 completely modifying the superficial forms of the rock, or perhaps from 

 the absence of definitely marked stratification. For even occasionally 

 when the rock itself is visible, there occurs doubt as to this point, the 

 fissures being so numerous and variable in direction, as to render it 

 impossible to pronounce which are, and which are not the lines of stra- 

 tification. 



82. From Deao to Kungos, the dip appears to vary between N. and E., 



31 By this term it is not meant to designate the granitic structure, but an aggrega- 

 tion of small grains, in which the difference of the felspar and quartz is often difficult 

 to be ascertained. 





