476 



THE GEOLOGIST. 



taining but few fossils (Pecten, Ostrea gigantea), and dipping to the 

 N.E. at an angle of 25° or 30°. 



" Below the lighthouse a very hard line-grained limestone, or rather 

 a calcareous freestone, presents itself intermingled with the other beds, 

 and containing Cytherea Verneuilii, &c. Some deposits containing 

 pebbles, ten or twelve yards thick, overlie the whole of these beds. 



" Beyond the Point St. Martin begin the cliffs of the ' Chambre 

 d' Amour.' They are formed of somewhat soft sandy limestones, with 

 0\jerculina, Ostrea gigantea, and Venus transversa ; here also may be 

 observed the same beds of hard bluish calcareous freestone with 

 Scalaria, &c, as those beneath the lighthouse. At the extremity 

 north of the little bay, the hard freestone is scattered, as it were, 

 through the softer sandy rock in the form of flattened detached 

 nodules, disposed in somewhat regular beds. Advancing from the 

 lighthouse, these nodules increase in volume and become blended 

 together in more continuous masses, till at last they entirely re|i>lace 

 the more friable rock, in which at first, beneath the lighthouse, they 

 only partially appeared. 



" The preceding description leads naturally to the following conclu- 

 sions : — 



" 1st. The nummulitic strata of the cliffs of Biarritz dip regularly 

 to the N.N.E., except for a short space where their inclination is in a 

 reverse direction, opposite the ophite rock. Consequently, in follow- 

 ing the coast-line from the commencement of the nummulitic cliff to 

 the point north of the Chambre d' Amour, the strata are in regular 

 sequence from the older to the more modern deposits. 



"2ndly. From the commencement of the nummulitic cliff to the Port 

 des Basques, there is a vast system of calcareous deposits, first arena- 

 ceous, afterwards argillaceous', and characterized principally by the 

 Guettardia Thiolati, Num. spissa, N. complanata, Serpula spirula3a> 

 &g. At the Port des Basques these beds disappear beneath the fol- 

 lowing deposits. 



" 3rdly. From the Port des Basques to the St. Martin lighthouse, 

 that is to say, through the whole mass of the point of Biarritz, and a 

 part of the Cote du Moulin, yellow or blue sandy calcareous deposits, 

 with rolled pebbles of flint or limestone, follow the strata previously 

 described. The fossils of the former beds are no longer found. Their 

 place is taken by the Eupatagus ornatus and the Nummulina inter- 

 media, which appear for the first time. 



"4thly. Finally, from the lighthouse to the extremity at the Chambre 

 d' Amour, a system of hard, fine-grained, calcareous freestone is de- 

 veloped, associated with Operculina sands. These rocks no longer 

 contain the Eupatagus ornatus, nor the Serpula spirulwa, but they 

 present a certain number of fossils, for the greater part identical with 

 the species found in the Paris basin, and unquestionably characteristic 

 of the Tertiary period. The Operculines seem here to replace the 

 Nummulites." 



•X- * * -X- -55- * * 



The work from which I have quoted contains an elaborate account 



