Correspondence — P. W. Stuart- Menteath. 833 



cos<ie-Es:F'OiNr3D:E3^G:Ei. 



THE GEOLOGY OF BIARRITZ. 



SiE, — In your pages of August last I described the reversal of 

 Pyrenean geology at Lourdes and Biarritz effected by M. Carez in 

 elaborate coloured sections of the Bull. Sac. Geol. for 1896, p. 379. By 

 a typographical error, the map of the intermediate Pyrenees obtained 

 from me by M. Carez in 1885 is referred to 1865. In spite of the 

 studied condemnation of the reply of M. Carez to the geologist who 

 had supplied his facts, I succeeded in re-establishing the Cretaceous 

 age of the rocks represented as Middle Silurian and Cambrian, in 

 which hundreds of Cretaceous Ammonites had been familiar to me 

 for thirty years. 



At Biarritz the supposed Lias, simultaneously figured in the same 

 manner, has given birth to a unanimous selection of that locality 

 as a type and proof of those Alpine paradoxes similarly created by 

 MM. M. Bertrand, Carez, L. Bertrand, Bergeron, Seunes, and other 

 officials of the French Survey. The question has been reduced to 

 the decisive test of a boring of 104 metres deep, which boring has 

 exactly proved the contrary of the views in question as figured by 

 M. Bergeron in Bull. Soc. Geol of 1900, p. 24. This boring has 

 exactly confirmed my predictions of the same Bulletin, p. 614, as 

 well as the detailed sections which I furnished to those interested at 

 the Sorbonne. An elaborate attempt to explain away this decisive 

 boring has been presented by M. L. Bertrand in Bull. Soc. Geol., 

 1902, p. 83 ; and all his alleged facts have been refuted by 

 M. Seunes in the Compte Rendu of the meeting of the same society 

 on 6th April last. 



The documents enumerated will enable any geologist to judge the 

 method applied at Biarritz by the authors of the same paradox in the 

 Alps, Montague Noire, Provence, Corbieres, and such Pyrenean 

 localities as Salies du Salat and Lasseube. Eight months of recent 

 observation in the Alps, and repeated study of the other localities 

 mentioned, have convinced me that Biarritz has been correctly 

 selected by all the authors in question as a perfect sample of their 

 work. The entire problem is precisely similar to that already settled 

 at Lourdes. 



In the hands of M. Seunes the problem attains the final stage of 

 the process of proof invariably employed. This geologist is really 

 familiar with the ground. In 1886 he was sent to me with a letter 

 from the last two Professors of geology at the Sorbonne, begging me 

 to supply him with my unpublished data, and promising that my 

 published work should be the basis of his Thesis. Starting with all 

 the new facts collected by my assistants and myself, he has completed 

 his knowledge by yearly work. Consequently he has admitted, 

 after 16 years, that every supposed fact cited as proving the presence 

 of Trias at Biarritz is absolutely erroneous. Yet he affirms the 

 correctness of the theory left standing on exploded fallacies alone. 

 If he did not do so, his work would be treated as my own numerous 

 papers, and as those in the Bull. Soc. Geol. of 1893 by the Staff 



