iSS HOLLAND: CHARNOCKITE SERIES. 



iron-ores nor garnets have been observed in the peculiar lenticular 

 inclusions, although they are abundant enough in the associated ordi- 

 nary members of the charnockite series. 



At present I am unable to recall any precise parallel 

 for these peculiar inclusions. Their lenticular shape and their 

 occurrence in trains along the same band of the charnockite series 

 suggests that the lenticular shape is the result of the " pinching" 

 of a once continuous band. The conversion of a band of tough 

 basic rock into lenticles, instead of the mere spreading out of the 

 constituents into a thinner band, illustrates very prettily the various 

 degrees by which different rocks yield under pressure. Asa general 

 rule the more basic rocks are, under pressure, less plastic than acid 

 ones and so take on simple foliation less readily; it is in consequence 

 of this fact, Adams thinks, that basic masses are so frequently found 

 in trains of fragments included in thinly foliated siliceous forms 

 instead of forming thin basic leaves. 1 



The western margin of the Nilgiri mass appears to be as 

 Western margin of the precipitous as the southern ; but in the north 

 mass * it slopes away through the portion known as the 



Nidumalai range till it reaches the lower-lying plateau of the 

 Mysore State. In the Wainad to the north-west and in Malabar on the 

 west the average strike of the foliated rocks is N.-N.-W. — S.-S.-E., but 

 we have no details as to the connection between the physical geology 

 and the change of strike which probably occurs near the line of junc- 

 tion between the Nilgiri mass and the gneisses of the Wainad and 

 Malabar. The disturbances recorded by Dr. W. King 2 in the former 

 locality, and those described by Mr. Lake in the Malabar District, 8 

 would be of much greater interest if we possessed more precise data 

 than is obtainable from a mere macroscopic description of the rocks. 

 The interesting questions connected with the geological relations of 

 the Nilgiris to the surrounding low countries must, therefore, be left 

 for a while in this incomplete condition. 



1 See Amet. Joum. Sci., Vol. L (1895), p. 62. 



2 Rec. Geol. Surv. Ind., Vol. VIII, p. 37. 



a Mem. Geol. Surv. Ind., Vol. XXIV, plate II. 



< 70 ) 



