402 Journal of tivo Trading Travellers 



that in neither case could pebbles be furnished in such a way 

 as to afford materials for those great deposits of gravel and 

 conglomerate, which we observe in rocks that must have been 

 formed at various epochs; the coasts present lines of shingle or 

 sand, more advanced in cases of the embouchures of rivers into 

 tideless, generally calm, or nearly tideless seas, and the rivers 

 afford mere lines of pebbles. To make these materials availa- 

 ble in the formation of extensively deposited gravels and con- 

 glomerates, some greater and more general force than the ac- 

 tion of seas on their coasts, or rivers on their beds, must col- 

 lect them together. This force it seems natural to seek in 

 masses of water more or less voluminous according to circum? 

 stances. To produce these at various times and in greater or 

 less abundance, the various dislocations of strata everywhere 

 so observable, seems adequate. It is now known that moun- 

 tains have been raised at different epochs, and that horizontal 

 strata, even those deposited at comparatively recent geologi- 

 cal epochs, have been shattered and broken into faults, a large 

 proportion of which are duly covered by the gravels that have 

 been termed diluvium. Can we imagine that such great con- 

 vulsions and disruptions of our planet's crust could have been 

 unaccompanied by violent movements in the mass of waters, 

 and that debacles, as they are called, have not been fre- 

 quent and great? It seems but rational to infer that such 

 debacles or deluges must have more or less resulted from every 

 great convulsion, and have been more or less extensive accord- 

 ing to the power of the disrupting force. Such causes could 

 easily form the extensive gravel and conglomerate deposits: 

 we now observe, not only by the ir own destructive power, but 

 also by amassing all the river and sea-shore gravel within their 

 influence. 



According to this theory, the extent of gravels would cor- 

 respond with the extent of the disturbing forces, and would 

 be general where these forces were applied generally, and par- 

 tial where these forces were applied partially. 



Substance of the Journal of two Trading Travellers, 

 and of the Communications of a Missionary, regard- 

 ing their recent visits to the Countries in the rear of 

 the Portuguese Settlement at I)e la Goa Bay. By 

 Mr. John Centlivhes Cijase. 



[Read at the Spilth African Institution.^ 

 Whilk Messrs. Cowie and Green, part of whose notes I have 

 already submitted to the public, were remaining at De la Goa, 

 another expedition, under the management of two trading 

 travellers, named Scoon unci Luckie, had penetrated through 



