.(5 CEOLOGY OF THE SON VALLEY, ETC. 



collected by Mr. Wilson in the Bijawars, north of Surajpuaf. 

 It is one of the rocks mentioned by Mr. Holland in the Records, 

 Vol. XXX, page 37. In this rock the augites and felspars seem 

 to have crystallised to some extent simultaneously, ilmenite and 

 micropegmatite enclosing them both. The saussuritisation of 

 the felspars is here all but complete, The augites are largely 

 altered to green pleochroic uralite in a curiously irregular manner : 

 one crystal is still unchanged while the next one is entirely altered to 

 hornblende ; or else one end of the crystal is augite, the other end 

 uralite. Sometimes the change seems to take place along the 

 striations in the augite. In many cases the transformation is seen 

 starting from the outside ; but in one case also the centre of an 

 augite crystal is changed to hornblende. The hornblende is in 

 crystallographic continuity with the augite from which it is derived. 

 There is also some fibrous hornblende and some chlorite. The 

 ilmenite is still unaltered, 



T 5 3- is a dyke of uralite diabase from the gneiss at Barow. As 

 it has the character of the Bijawar lavas, it may be regarded as 

 belonging to the same period. Here the augite is entirely changed 

 into a pale uralite, which may reproduce the structure of the 

 original crystal or else forms a confused felted fibrous aggregate. 

 Only isolated irregular traces remain of the original augite. The 

 felspar is altered to saussunte to such an extent that in many 

 parts of the slide the structure is completely obscured ; yet in 

 other portions it has retained its clearness. Another of the 

 minerals which in the previous rocks was little altered here shows 

 conspicuous metamorphism : this is ilmenite now largely altered 

 to leucoxene. 



With the next rock T \%, we enter the Son region. The rock 



was collected by Mr. Hackett at Hardi 



at the western termination of the Son outcrop 



of the Bijawars. Here again some of the augite substance 



still remains as such, but in most cases it is much obscured with 



iron oxides and altered into a confused aggregate of decomposition 



( 76 ) 



