16 On Terrestrial or Epigeic Deposits 



from the shores of the sea ; and that beyond this zone, where 

 the surface is quite naked, traces are also found of the same 

 action at more than 1000 metres from the shore.* 



We at first attributed this phenomenon of erosion to actions 

 purely hygrometrical and mechanical ; we have since discovered 

 that it may be the result of the reaction of muriate of soda, on 

 carbonate of lime. 



Besides, whatever may be the cause of this phenomenon, if 

 we observe, that there is hardly any mountain in the Morea on 

 which we have not detected traces of ancient erosions perfectly 

 similar to that of the actual sphere of the aura-marina, that the 

 sea, at the sub-appenine epoch, cut the whole of the part emerg- 

 ing from the surface of the Peloponnesus by deep gulfs, so that 

 it must have been universally subjected to the influence of the 

 aura-marina ; that, besides, this reaction of the muriate of soda 

 on the carbonate of lime, produced soluble salts, which left iron 

 and silica in excess in the midst of calcareous debris, it must 

 be admitted that this red earth, for a long time observed on the 

 surface of our limestone mountains, is the product of their slow 

 destruction by atmospherical agents, aided by the aura-marina 

 during the whole period of emersion. 



Having now ascertained the principal agents of destruction 

 and reproduction on the emerged surface of the Peloponnesus, we 

 shall describe their products, first in the basins which have 

 remained without any external outlet since the sub-apennine pe- 

 riod, but whose deposits have been raised and excavated by the 

 shutting and opening of the subterranean drains. We shall 

 take the basin of Tripolitza as an instance, which presents hillocks 

 of alluvion at two different levels, though it is entirely enclosed 

 by high mountains. 



The basin of Megalopolis, shut during the sub-apennine epoch 

 and that of ferruginous alluvions, but opened afterwards by a 

 large breach near Carytene, and excavated deeply by the flowing 

 out of a lake and the increase of the fall in the torrent waters, 

 presents us with some peculiar phenomena. Passing from 



• Davy observed saline particles at a distance of more than 16 leagues from 

 the sea. They have even been detected at a distance of 45 leagues, afler a 

 violent tempest. (See Memoirs of the Academy of Manchester, January 

 1832.) 



