observed on Rocks on the Shores of' Greece. QVi 



rocks on which they are found, if they are sharp and stripped of 

 all vegetation, appertain to the sphere of action of the aura ma- 

 ritima; that if they are edged with moss and again covered 

 with lichens, analogy induces us to suppose that, at an anterior 

 period, they were continental and httoral surfaces. We shall 

 then be able, by means of this character, in spite of all the dis- 

 locations of the soil, the absence of pebbles, and cavities formed 

 by boring shells, and the frequent disappearance of recent dis- 

 tricts, to discover the trace of sea-shores at different periods. 

 This fact being undeniably established will, moreover, serve to 

 throw light on the question of the return of the sea upon sur- 

 faces which it had abandoned. Indeed this character is not 

 susceptible of being destroyed by the violent return of the sea 

 to the surface of continents. 



The direction of the grooves should be observed, if the sur- 

 face of the rock has permitted them to be developed to a great 

 extent. They will be in a normal direction to its horizontal 

 section, if the soil has not experienced great movements since 

 their formation. On the other hand, if their deviation be well 

 defined, it will enable us to discover the direction of the up- 

 raising disengaged from all tlie effects of anterior upraisings. 

 The examination of the surfaces of blocks imbedded in breccias 

 or of ancient alluvials, will demonstrate if already they had be- 

 longed to a terrestrial or a littoral surface. Touching induc- 

 tions relative to the time, which we can draw from the pheno- 

 menon of the erosion of the marbles and compact limestones, by 

 the effect of the aura maritima, I believe tliat, by reason of the 

 simplicity and the permanence of the phenomenon, they can ac- 

 quire a degree of probability as satisfactory as those derived from 

 a phenomenon operating on a greater scale, it is true, but much 

 more complex. It will be inferred, from the existence of small 

 horizontal terraces, lines of boring shells, and carious limestones, 

 imprinted on the more recent tertiary deposites, that the sea has 

 occupied many successive levels in the clysmian or diluvian 

 period^ which had not been acknowledged owing to particular 

 systematic and religious opinions. The comparison of the black 

 or deeply carious littoral zone, with surfaces analogous in the 

 interior, will offer means still more evident of discovering traces 

 of ancient shores, of separating ancient littoral caverns from con- 



7.9. 



