1870.] 



Deep-sea Researches, 



203 



rich ia Fossils, will be found to contain these fossils, for the most part, 

 in its coarser beds ; which were probably deposited in shallower waters, 

 like those which we found rich in Animal life along the shores of the 

 Mediterranean. The extremely fine stone that is used for carved work, — 

 so entirely wanting in " grain " that carvings executed in it look like casts 

 in Plaster of Paris, — contains, we were assured, few fossils except Sharks' 

 teeth, which, of course, dropped into it from above. We commend this 

 enquiry to the attention of Maltese Geologists, as one having an impor- 

 tant bearing on the solution of a problem of the highest interest. 



103. There is another condition, however, which maybe not less potent 

 in restraining within very narrow limits the Animal Life of the deeper parts 

 of the Mediterranean Basin, — namely, the stagnation produced by the 

 almost entire absence of Vertical Circulation. In the great Oceanic ba- 

 sins, if our doctrine (§ 124 et seq.) be correct, every drop of water is in 

 its turn brought to its surface and exposed to the purifying influence of 

 prolonged exposure to the air. From this movement, the water of the 

 Mediterranean may be said to be virtually excluded ; and, as has been 

 already shown (§ 95), the deeper part of the basin has no Circulation of 

 its own, either horizontal or vertical, which will have the effect of bring- 

 ing its water to the surface. It is difficult, in fact, to conceive of any 

 agency that can disturb the stillness of the abyssal depths of a basin which 

 is completely shut in by a wall that rises more than 10,000 feet from 

 its bottom. How far this affects the condition of such depths, in respect 

 to the diffusion of the Organic matter and the Oxygen required for 

 the support of Animal life, must be a matter of future inquiry. 



Gibraltar Current. 



104. The term "Strait of Gibraltar" is usually applied to that space 

 between the coast-lines of Spain and Morocco which is bounded on the 

 west by Capes Trafalgar and Spartel, and on the east by the two 

 " Pillars of Hercules," — namely Europa Point, which forms the southern 

 extremity of the Rock of Gibraltar, and Jebel Musa or Apes Hill on the 

 Barbary side. As Admiral Smyth justly remarks *, however, we may cor- 

 rectly include in the Strait the whole of that funnel-shaped entrance from 

 the Atlantic, of which the western boundary is formed by a line from Cape 

 St. Vincent on the north to Cape Cantin on the south, the whole of the 

 water within this entrance being affected by the surface-draught into the 

 Mediterranean. It was considered by Major Rennell that there is a general 

 " set" of Atlantic water between Lat. 30° and 45° N., and from 100 to 

 130 leagues off the land, towards the entrance of the Strait, the rate of 

 movement being as much as from 14 to 17 miles per day. This estimate, 

 however, is regarded by Admiral Smyth (Joe. cit.) as excessive ; although 

 he thinks that such an indraught may possibly occur during the long pre- 



* The Mediterranean, p. 158. 



