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



which the Earth's crust was deficient in density. I then took 

 one step forward and suggested that it was a zone of tension. 

 I will now take another step forward and suggest to you that 

 there has occurred an actual opening in the sub-crust, and that 

 the outer crust has fallen in owing to the failure of its founda- 

 tion : I suggest that the Ganges plains cover a great rift in the 



Earth's crust. 



The Earth is a cooling globe ; an increase of temperature 



occurs as we descend into mines ; and this temperature gradi- 

 ent is a proof that the Earth is losing heat by conduction 

 outwards. The discovery of radium has not affected the argu- 

 ment . 



The smaller bodies of the solar system, the Moon and 



other satellites seem to be cold ; the Earth has a cold exterior 

 and a hot interior; the larger planets are believed still to 

 display heated surfaces, whilst the Sun is still a globe of fire. 

 The inferences are warranted that all the bodies of the solar 

 system were hot at one time, and that the smaller have lost 

 their heat. So I say that the Earth is a -cooling body. The 

 rock composing the crust and sub-crust is however a bad 

 conductor, and the interior of the Earth will not shrink away 

 from its crust, as has been assumed in the Contraction theory. 

 The inner core of the Earth is in fact not losing heat appre- 

 ciably. The outer shell was the first to lose its heat, then the 

 shell below it, and the sub-crust is now losing its heat more 

 quickly than the interior core. As the outer shells contract 

 from cooling, they become too small for the core, and they 

 crack. Supposing we had here a great globe of rock, red-hot 

 throughout ; how would it cool ? Can you imagine it cooling in 

 such a way that the core became too small for the outer shell, 

 and the outer shell became wrinkled I No ; the outer shell 

 would cool first, and would crack. 



The outer shell of the Earth was the first to crack millions 

 of years ago: now a lower shell, the sub-crustal shell, is crack- 

 ing. When a crack occurs in the sub-crust, parts of the upper 

 crust fall in. 



You will see that this Indus-Ganges trough has the appear- 

 ance of a crack. And there are reasons for believing that these 

 Himalaya have been split off from this ancient table-land and 

 have been moved northwards and crumpled up into mountains. 

 This Assam plateau is stated by geologists to resemble in its 

 structure and rocks the Indian table-land; Assam has been 

 split off and moved away. 



Here are the Bengal coal-fields, and just opposite on the 

 other side of the trough are the Sikkim coal-fields; and the 

 coal in the two places is similar. The rocks of the outer 

 Himalaya have been very much crushed, but they still bear a 

 resemblance to the rocks of the Vindhyan table-land. 



Here are the Arravalli mountains which end now at the 



