(m the Surface of the Morea. 15 



iron in grains ; a composition which seems to shew that it pro- 

 ceeds from the destruction of our secondary limestone formations, 

 all of which are more or less siliceous and ferruginous. In 

 some localities, kidney-shaped concretions slightly crystalline are 

 also met with, which seem to me to be formed of a mixtui-e of 

 ferruginous calcareous spar, and the carbonate of the peroxide 

 of iron, a substance which establishes that a chemical action has 

 contributed to the production of the red earth. Mixed some- 

 times with calcareous gravel and with iron in grains, it is accu- 

 mulated in the fissures on the summits of mountains, and one 

 of these heaps was pointed out to me as a gold-mine, which had 

 been abandoned (mountain of Tropezona, near Kelli, in Argo- 

 lis) ; but I saw nothing to justify such an opinion. We have 

 evidence of the ancient date of the formation of this earth on 

 the continental surface of Greece, in its abundance in the midst 

 of the ancient alluvium of the valleys, and even in certain de- 

 tritic deposits of the sub-apennine tertiary formation, as the red 

 conglomerates of Marathonisi, and the neighbourhood of Sparta, 

 which represent the deposit of the sub-apennine marls at the bot- 

 tom of the steep shores. One should suppose, from the com- 

 position of this earth, the presence of iron and silica, either dis- 

 seminated or in grains, the constancy of its character at great 

 distances, and especially its exclusive presence at the surface of 

 secondary limestone, that it proceeds from their slow destruc- 

 tion. But if we examine the surface of rocks in the interior of 

 the continent, we see it every where covered with green matter 

 and lichens ; so that if any destructive action was going on at 

 this moment, it could only take place through the medium of 

 the vegetation. We believe, in fact, that such action takes 

 place : Colonel Borry has pointed out lichens to us almost en- 

 tirely composed of the carbonate of lime, which have the pro- 

 perty of assimilating this substance, as the niolluscae do in sea- 

 water, and thence result small cavities ; but it is not to this fee- 

 ble action alone that we can have recourse to explain a produc- 

 tion so abundant as the red earth. 



In the memoir which we pubhshed in 1801, on the action of 

 the sea, and of the aura-marina on calcareous rocks, we demon- 

 strated that this latter action entirely corroded calcareous sur- 

 faces at a height of more than 50 metres, and at a great distance 



