• • 



XC11 



Journal of the Asiatic Society of Bengal. [N.S.. XII, 



I suggest to you that a crack in the sub-crust has extend- 

 ed from Cape Comorin to Cambay, and that as this crack has 

 occurred the Western Ghats have been elevated. The crack 

 has been filled by masses of fallen rock and by alluvial deposits 

 brought down by rivers. 



Geologists have shown that this range consists, from 

 latitude 20° to 16°, of the lavas of the Deccan, comparatively 

 recent rocks, whilst from latitude 16° to 8° the range consists 

 of ancient metamorphic rocks. The rocks of the northern part 

 of the range are of a different age and structure and origin 



from the southern. 



Nevertheless geodesists contend that this is one and the 

 same range: the rocks composing it have had nothing to do 

 with its elevation. The Western Ghats have been elevated 

 after the Deccan lavas had become solidified into surface rocks. 

 Their elevation has taken place in the Tertiary age. 



Now I will turn to the Eastern Ghats (Plate A); at Madras 

 and at Vizagapatam we find the plumb-line hanging towards 

 the sea. Here we have the same phenomenon as we witnessed 

 at Lucknow and at Bombay, the plumb-line turns away from 

 the mountains. I will not repeat myself, but I suggest again 

 that this coastal zone, like the western, covers a sub-crustal crack. 



I told you just now that in the last 300 years there had 

 been 64 destructive earthquakes in India: of these 58 had 

 occurred along the Indus-Ganges trough. Where did the 

 remaining six take place ? Three of them occurred on the 

 Bombay-Surat coast; the other three on the Madras coast. No 

 destructive earthquakes are recorded as having occurred at 

 Hyderabad, or at Bangalore, or at Nagpore. 



The ancient table-land of India is in the shape of a 

 triangle, but its two wings, Assam and Cutch, have been 

 severed from the main body : this may have been due to the 

 coast-line cracks. 



Assam- Bengal has had 20 destructive earthquakes in the 

 last 300 years, and though only 6 have been recorded in Cutch 

 and Sind, yet this western fragment of the table-land is of 

 seismic region. In 1819 Bhuj was destroyed and every town 

 in Cutch was injured ; numerous fissures were seen throughout 

 the land. North of Sindhi a drop 16 feet deep and 50 miles 

 long suddenly appeared on the plains which had hitherto 

 been as level as the sea. On account of its sudden appearance 

 across the old bed of the Indus it was named by the in- 

 habitants the Allah Bund, and by this name it is now known 

 in geography. It was due to the subsidence of a large are; 

 to the south. 



Many of the destructive earthquakes of Sind have not 

 been recorded in history, but the ruins of strong buildings with 

 human bones buried below them are evidence of sudden de- 

 struction by earthquake. 



