1835.] Geology of the Bombay Islands. 341 



extensive portion of land in Salsette, which is dry at low 

 water, is situated beyond the influence of any current save 

 that of the tide, which it must be admitted, however, is 

 extremely powerful. 



' There seems no reason, then, for supposing that this bank 

 has been formed by matter forced down by the agency of 

 running water from the Ghauts, as some have concluded, 

 because, it exists where there are no rivers to produce accu- 

 mulations, and it is broadest at the mouths of the smallest 

 rivers. 



. In bringing forward proofs of extensive changes and 

 violent convulsions, we have endeavoured to exclude 

 theoretical considerations, and probability is only implied 

 when we observe that the different islands in the bay may 

 have been the continuation of the high land in Salsette 

 and Tull, whose communications have been submersed, and 

 whose bases are now washed by the overwhelming waters 

 of the ocean. 



Article III. 



Geology of JEstramadura, and the North of Andalusia. By 

 M. F. Le Play. ( Ann. des Mines, vi. 297. 477J 



The portion of country described in this paper is included 

 between the Rivers Tagus and Guadalquiver, on the north 

 and south, and between La Mancha and Portugal on the 

 west and east. Interesting as this district is, both in a phy- 

 sical and moral point of view, it is strange how little infor- 

 mation we have respecting it. The cities of Seville, Cordova, 

 and Badajoz, are the only names belonging to it which are 

 known to the rest of Europe, while Truxillo, Merida, and 

 Medellin are merely noticed as military stations during the 

 Peninsular war. Estramadura, and the Sierra. Morena, 

 which border it on the south, form an inland country, at a 

 distance from high ways, and remarkable for its vast pasture 

 lands, which serve to support large flocks of Merino sheep. 

 Onaccount of the paucity of the population, no travellers have 

 examined its Geology, for, the only allusion, in a scientific 

 point of view, to this portion of Spain, which M. Le Play 

 could discover, was in the small work of G. Bowles, which 

 was translated into French in 1776. The maps of this dis- 



