334) Captain Puillon-Boblaye on the Tidal and other Zones 



and makes the dark colour of the zone, which exists immediate- 

 ly above the tides, more distinct. Numerous asperities, clefts, 

 and caverns contribute to make its base appear of an intense 

 black. Above the tint is softened, but the transition to the suc- 

 ceeding zone remains always strongly delineated. 



The latter is generally of a dazzling white, yet, as it im- 

 presses its colour on the rocks themselves, it shows in some lo- 

 calities the blood-red colour, or flower of the peach, or the straw- 

 yellow of lithographic limestones. Above, there appears a zone 

 of a uniform grey, whatever be the nature of the rock : vege- 

 tation there commences, and is pointed out by some patches 

 of a dark green colour. 



Finally, at an elevation much higher than the shore, where 

 much exposed to the violence of the tides, an elevation that 

 rarely surpasses from thirty-five to forty yards, there appears a 

 vegetation of a brilliant green, although a little dark, which ex- 

 tends even to the summits of the mountains, if the rapidity of 

 their acclivity does not prevent it. These are the different zones 

 Avhich I am now to describe. 



The Zone of the Tide. . 



The tides in the Mediterranean are so inconsiderable, that we 

 cannot distinguish by observation their effects from those of the 

 diurnal influences of breezes and variable winds, at least the at- 

 tempts that I have made in this respect have been fruitless. 

 Yet no one can doubt the existence of these tides, when in calm 

 weather he sails along the shore. 



In fact, it appears that the tide balances itself constantly be- 

 tween the limits of a little zone which is not three decimetres in 

 height, but which is defined in a manner so conspicuous, that it 

 announces the influence of a permanent and regular cause. 



In the localities where the tide has little energy, as in the 

 ports of Napoli and Navarino, it is characterised by a marine ve- 

 getation of a yellow colour, which detaches itself in a very con- 

 spicuous manner on the dark colour of the lower part of the 

 shore. On the contrary, wherever the mechanical action of the 

 tide, doubtless seconded by chemical actions, has been able to 

 attack the limestone, and this is a very general case, this little 



