194 



DEEP SEA BRECCHIAS. 



sium, where a pinnacle of rock rises from a depth 

 of a hundred and forty fathoms, until it reaches 

 within thirty fathoms of the surface, deep water 

 surrounding it. On the other hand, conglome- 

 rates of rounded pebbles, with associated beds 

 of sand, are forming nearly on a level with the 

 sea, in consequence of the gradual destruction of 

 serpentine islands in the gulph. In these, wood 

 is becoming imbedded in considerable quantity. 

 Such insulated conglomerate beds, or beaches, 

 have usually a little lagoon in their centres. 



Brecchiated beds accumulating around the 

 bases of rocky submarine peaks rising in deep 

 water at a distance from land, are more likely 

 to contain imbedded organic remains than such 

 as are formed along shore. Round their bases 

 will accumulate beds of gravel, shells and corals 

 belonging to various zones of depth. Such is 

 the case, as we found by dredging, round the 

 peak of rock in the neighbourhood of Cape Ar- 

 temisium already mentioned. 



Owing to the peculiar form of many of the 

 ravines along the coast, their entrances beneath 

 the water may become choked up with a bar 

 of conglomerate, banks of pebbles becoming 

 rapidly consolidated. Then the deep basin inside 



