Dec. 1861.] Gtdogi *j On Frf'ghtrrics. 257 



This constant appearance of the iron whenever a mineral mass 

 has been projected from below, renders it probable that vast 

 quantities of the metal in a molten state lie beneath these hills in 

 subterranean depths, in which laboratories of nature, her hand 

 f( rms the mineral combinations that are subsequently cast upon 

 the surface. 



This point terminates the history of the elevating causes that 

 have produced the plateau known as the Neilgherry Hills. 



I shall next consider those which are now operating conversely 

 to reduce these mountains again to their ancient level, and even- 

 tually many thousand years hence to blot them out wholly from 

 the map of the earth's crust ; carrying their debris far away as the 

 materials for new Continents. Already had the destructive agent, 

 water, commenced its operations, when the creative principle fire 

 was forming the Hills. We have learnt that the ivaters raised by 

 the fire, at their recedence, grooved out of the earthy-mass ducts 

 for their own descent, and it is believed that the meeting of these 

 antagonist elements, when the waters in part descended through 

 the funnels and fissures in the syenite upon the fires below, led to 

 the partial dissipation of both, and from their destruction arose a 

 third power probably as great as either in producing geological 

 events, viz. 



Steam. — The effects of this new agent to expand and release 

 itself from the narrow limits it was confined in, produced many of 

 the rents and crevices, in the plateau, subsequently filled by 

 metals and minerals ; while it also shattered the base of the rocky 

 buttresses to an extent, in many cases, adequate to produce such 

 effects as we find below the Khoondah mountains, where vast 

 heaps of peaks lie in the subjacent valley, these peaks having 

 been the summits of the mountains whose bases fell by the ex- 

 plosive action of steam. 



More recent deluges excavated during their recedence, the 

 numerous vallies now furrowing the surface of the Hills, and the 

 streams flowing along their channels afterwards contributed to 

 wear away the soil, assisted by heavy rains that washed into their 

 beds portions of the banks of the adjacent eminences. As the 



