216 GEOLOGICAL OBSERVATIONS IN FRANCE. 



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cess of salt marshes; the tide flowing into basins formed in 

 the sand, where the \yater standi some time to evaporate be- 

 fore it is boiled down. 



The cliffs do not reappear as far as fort de la Ilougue, 

 where I was obliged to give up my design of doubling cape 

 Barfleur, viewing the real granite in its native situation. A 

 idisngrecable event, which it would be useless to mention, 

 obliged me to proceed directly to Valogne. On this road I 



Schist. continually met vyith argillaceous schist, which as it proceeds 



in land forms a series of woody hills, rising in height as they 



Furze sown to recede from the coast. Near Valogne the ulex EjiropceuSf 



manure. furze, is seen in abundance. It is sown there, to be burned 



on the land as a manure. 



Woody coun- From Valogne to Cherbourg the country is w-oody, and the 

 ^' soil re<]dish. Cherbourg is built on a substratum of light 



Steatite. ^rcen steatite, very greasy to the feel, in laniinse more or less 



Curved. In some places they are in separate pieces, coarse 



ITarbourof grained, and easily broken. The new basins for the harbour 

 ler ourg. ^^^ Cutting out of this rock. Large nodules of true granite, 

 and veins of quartz, are included in the' steatite. 



The mountain of Roule, a little to the south-south-east of 

 Cherbourg, may be considered as constituting the cliff. Ij; 

 terminates abruptly toward the town in a precipice about 4Q 



Petrosilex. toises htgh. It consi'^ts of a kind of dull petrosilex, with a 



shelly fracture, in some places reddish, in others whitish, 



much like that of Ravenoville, but evidently in strata seve^ 



ral feet thick, all rupning S S. E. and N. N. W. Quartz 



Quarried for crystals are occasionally found in it. This rock is wrought 

 the haroour of - , , _ , , , , ,, , • i * 



Cherbourg. i^r the works of the harbour, be.ng blasted in large masses. 



Hilly pcuntry. Between Cherbourg and St. Lo the soil is variable. Thence 



to Aulnay and on to Falaise it is hilly, and woody, but the 



trees are in general low. The usual direction of these hills 



is noith and south, and they diminish \n height as they ap-- 



Schist. proach the coa*it. They consist of a micaceous argillaceous 



schist, which does not effervesce with acids, and includes no 



ciganic bodies. In some places it passes into true slate. 



Limestone '^^»r Villers hbv^^eyier, in the Hlstrici of Cam, is found a gra- 



Cattlefed on ^'"^"^s limestone containing a prodigious quaiitity of belem- 



furve; - '' nhes. Tiic lurze on the downs is employed for feeding cattle. 



The 



