SKETCH OF THE GEOLOGY OF BIARRITZ. 



475 



cliff begins a long rectilineal escarpment, which extends to the ' Port 

 des Basques,' marked out with great regularity to the N.N.E., for the 

 distance of rather more than a mile. Opposite the point where this 

 cliff begins, there rises in the sea a rock much more considerable 

 than those we have hitherto met with, and which is designated by 

 M. Thorent the ' Bocher du Goulet :' it is formed of grey-blue lime- 

 stone, tolerably hard, and worked as building-stone ; it dips to the 

 N.N.E., and encloses a great quantity of fossils." (This rock has been 

 so much worked for building that it is below high -water mark, 1861.) 

 " The cliff itself, throughout its whole extent, presents a very uniform 

 appearance. It consists exclusively of alternate beds of bluish clay 

 and soft limestone of the same colour, dipping regularly to the N.E. at 

 an angle of about 40° or 45°. The only fossil found there is the 

 Serpula spindcea" (As you approach the Port des Basques, the 

 beds become richer. On the shore, imbedded in the rock, I have 

 found several varieties of shells, and also a good deal of wood.) 

 " This long clay cliff terminates abruptly at the Port des Basques 

 against the promontory of Biarritz. 



" Here begins a new system of deposits, harder than those which we 

 have hitherto described, and to this circumstance is due the singular 

 aspect of the whole of this mass of rock, fantastically worn by the 

 sea. * * * It is composed of yellow arenaceous limestones to- 

 wards the south, intermingled with beds of arenaceous limestone of a 

 bluish shade, which, advancing northward, become more and more 

 abundant. These limestones enclose an enormous quantity of small 

 nummulites (N. intermedia), which of themselves almost form small 

 beds ; the Eupatagus ornatus is also sufficiently plentiful ; finally, 

 round the 1 roche percee,' the Scutella subtetragona is frequently met, 

 with ; this fossil has, no doubt erroneously, been stated to be found 

 in the Dax beds. * * * 



" In the regular strata, rolled pebbles of hard grey subsaccharoid 

 limestone, and also of black flint, may be frequently observed ; 

 they are the debris of the siliceous limestone of the chalk period, 

 similar to those in the escarpment of Bidart, and which must have 

 existed as rocks on the shore of the sea in which the nummulitic beds 

 were in process of formation. 



" The whole strata which form the mass of the rock at Biarritz are 

 overlaid by a very modern deposit of yellow sand, which on the 

 Attalay attains the thickness of at least fifteen or twenty yards. 

 (This modern deposit beyond the Attalay, beneath the Empress's 

 chapel, contains wood and great masses of vegetable matter.) 



" Beyond the point of Biarritz begins the ' Cote du Moulin,' bor- 

 dered at first by little escarpments, surmounted by some sand-hills. 

 These escarpments are formed of a very sandy bluish limestone, with 

 some yellowish bands containing an abundance of the Nummulina 

 Biarritziana, also the Eupatagus ornatus, the Schizaster rimosus, &c. 

 Low sand-hills occupy the space beyond, for a distance of 600 or 650 

 yards, after which follows a steep cliff, twenty-five or thirty yards high, 

 composed of bluish sandy limestones, with some yellow bands, con- 



