GEOLOGICAL FEATURES. 9 



by Lala Kishen Singh, Sub-Assistant of this department. Consider- 

 able difficulties were met with in carrying out this work, chiefly 

 owing to the season and the abnormal rainfall : Mr. Stonier had 

 completed the greater portion of the work when he handed over 

 charge to me in October. By the end of November, we had succeeded 

 in opening over 3,500 feet of drives, and the sampling of the reef 

 was then undertaken by Dr. Hatch. 



B.-GEOLOGICAL FEATURES. 



The chief topographical and geological features of Wain^d have 

 already been described by Dr. King (Rec. Geol. Surv. Ind., 

 Vol. VIII) who included most of the rocks found in the area visited 

 by him in the archaean system (crystalline or gneissic series). 



He describes four different varieties of gneiss : of these three have 

 „ „. , certain points of resemblance to one another, 



Dr. King s r ' 



classification. but the fourth, which he calls a " syenitoid and 



quartzose gneiss'' is quite distinct and was formerly placed in the 

 Upper (Bengal) division of the gneisses. The great advances 

 recently made in our knowledge of the petrological characters of the 

 rocks of Southern India, and especially the work of Mr. Holland, 

 have now proved that this rock, to which in 1893 Mr. Holland gave 

 the name of ckarnockite, is not only younger than the majority of the 

 biotite gneisses, but is intrusive in them. 1 



The rocks then in south-east Wain£d fall into five classes :— 



1. Gneisses. 



2. Members of the ckarnockite series. 



3. Ferruginous quartzites. 



4. Intrusive rocks, including older and younger basic intru- 



sives, biotite granite, and mica-bearing pegmatites. 



5. Quartz reefs. 



1 Holland. Mem. Geol. Surv. Ind., Vol. XXVIII, Pt. 2, 1900. 



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