EVIDENCES OF LOCAL EARTH-MOVEMENTS. 139 



III.— EVIDENCES OF LOCAL EARTH-MOVEMENTS. 



Whilst the area now under consideration has probably 

 suffered from no intense folding movements since the consolidation 

 of the charnockite series, it has nevertheless suffered from earth- 

 movements of a milder kind ; indeed it is hardly likely that any 

 region of the globe has submitted to the differential effects of un- 

 interrupted denudation without the production of at least normal 

 faults. As it must always be a matter of some difficulty to determine 

 the nature and amount of earth-movements in areas covered only by 

 crystalline rocks, the conclusions here based on the recognition of 

 lines of dislocation must only be regarded as working hypotheses to 

 be checked by more extended observations. 



So far as can be judged by the limited number of observa- 

 tions which have hitherto been made, the south of India was sub- 

 jected to at least two main systems of folding in pre-Cuddapah 

 times. The last of these produced folds in a N.-W. — S.-E. or 

 N.-N.-W. — S.-S.-E. direction, and outlined the position of the West- 

 ern Ghats, as well as of the N.-W. — S.-E. tongues of Dharwars 

 which run obliquely across the Mysore State and adjoining districts. 

 It is the effect of this folding which I believe to be shown in the 

 neighbourhood of Salem in the form of N.-E. — S.-W. transverse 

 dislocations. In probably every region which is folded such trans- 

 verse dislocations, 1 or " heaves " as the miners call them are 

 formed by unequal compression of different parts of the same fold 

 and in many parts of the south of India the existence of these in 

 the older rocks ought to be brought out by careful mapping. 



Brecciation (" trap-shotten") bands. 

 In the area under discussion the evidence, though of a limited 

 nature, appears to point to the fact that such a dislocation line runs 



1 f 'TransversalenorizontaIverschiebungen,»" Blatter," or "decrochements horizontal* 

 (Ueim and Marjjene, " Die Dislocationea der Erdrinde," iSSS, p. 71). 



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