MEKACHANITE IN MICACEOUS SCHIST- £5 



brooks of Sestri and Fegli bad inundated this part of the 

 shore, after washing the surface of the surrounding moun- 

 tains. 



This observation, frequently occurring, led me to suspect, therefore pro- 



that the black sand on this shore was furnished by the l*bly brought 



* trorn the 



mountains, that poor their waters into the Varenna, as well mountains, 

 as by other torrents running between Sestri and Pegli ; that 

 the conflict between these fresh water streams and the waves 

 of the stormy sea directed against the shore effected a wash- 

 ing of the earth containing the mechanite; and that thus 

 the mineral was deposited in the form of sand on the shore, 

 while the earthy substances, being less heavy, remained some 

 time longer diffused and suspended in the seawater. 



This conjecture inspired me with the hope of finding the Torrents 



native bed of the mechanite in the mountains above Sestri traccd t0 their 



sources m 

 and Pegii, which form the streams of the Varenna and Liguri*. 



Other little torrents, that flow across that shore. I deter- 

 mined therefore to trace these torrents to their sources, and 

 at the same time ascertain the nature of the mountains. 



The torrent of Varenna divides the territory of Sestri 

 from that of Pegli. Though dry in summer, it is above a 

 hundred yards broad at its month. It forms the edges of 

 the plains that border it on both sides, and adds to them 

 annually; but it frequently resumes its rights, and destroys 

 in a day the work of ages. 



The torrent comes from a chain of magnesian mountains, Mountains- 

 which shelter the fine plantations of Pegli from the north from which 

 wind, and render its climate the mildest in all Liguria. To they P roc?ed ' 

 the right of this torrent, above Pegli, begins a system of 

 mountains of micaceous schist, which runs sometimes into 

 shining at others into micaschist. This system is continued 

 to the south-west all along the Apennines/and forms the 

 nucleus of these mountains in the western range to their 

 junction with the maritime Alps. It is between Pegli and 

 Sestri only that we can properly establish the commence- 

 ment of this system ; for the slaty schist, and secondary 

 Jimestone, extend from the serpentine chain of Bracco, in 

 the eastern range, as far as the Scoglio de St. Andrea, a dis- 

 tance of about eight and twenty miles, where they suddenly 



disappear, 



