338 Captain Puillon-Boblaye on the Tidal and other Zones 



was only from one yard to one and a half in breadth. I saw, 

 besides, that the groove hollowed at the base of the rock joined 

 every where at the level of the tide a succession of caverns and 

 cavities more or less deep, which the dimensions alone distin- 

 guished ; that to the one as well as to the other corresponded 

 the hnes of fissures crossing in different directions, and that their 

 meeting in a greater number seemed only to have promoted 

 their enlargement, or the passage from the state of a cavity, 

 partly submarine, to the state of a littoral cavern. 



An observation already made at Napoli, at the foot of the 

 fortress of Itskale, was confirmed here. Cavities which were only 

 a yard in length, with a sinuous and rounded outline, attained 

 a height of from 30 to 40 yards. Their great axis, constantly 

 placed in the plane of a scarcely perceptible fissure, offered no 

 trace of erosion, nor the cavities any apparent continuity. I 

 mention them here for the purpose of noticing their relation to 

 the fissures, for I do not believe that they could otherwise be 

 the result of littoral influences. I believe them rather analo- 

 gous to bone-caves, produced partly by the flowing of conti- 

 nental waters. The interior of the cavern presented some pe- 

 culiar circumstances, which I have no doubt will be found in 

 all the littoral caverns. The rounded form of the inferior part 

 of its vault and its walls, showed that the fissures had only 

 acted by facilitating the chemical and mechanical action of the 

 tide, and afterwards hastening the fall of some angular parts of 

 the vault. The rock was grey marble, in thick layers almost 

 vertical, and perfectly homogeneous. We found at the surface 

 of the rock parts decayed, and again covered with black testa- 

 ceous matter, of which I shall speak soon. 



No opening could be discovered either at the summit, or 

 at the most remote part where the rock was bare ; in a word, it 

 did not differ from the numerous cavities of the line of the tide, 

 but only by its greater dimensions. 



The bottom, which rose quickly towai'ds the interior, was 

 covered with sea-weeds, pieces of wood, and other bodies capable 

 of floating, and some rolled pebbles, all identical witli the rock on 

 which they rested, a character very essential to be remarked. 



It is not, then, one of those caverns of erosion, with succes- 

 sions of chambers and galleries, and with smooth walls, filled 



