334 Correspondence — P. W. Stuart- Menteath. 



Officer who for ten years revised the topographical maps. That 

 officer's practice in accurate mapping and my own practice in 

 responsible engineering work compelled each of us to leave the 

 Societe Geologique when required to divorce theory from fact. Under 

 Elie de Beaumont such divorce was inevitable, in the opinion of the 

 new and exactly contrary school. Those trained to repeat either 

 formula find the one as little embarrassing as the other. In all the 

 localities already mentioned, I have found that admitted fallacies 

 originated the paradoxes which survive. So at Biarritz the imagined 

 Trias originates a fresh fallacy for each disproved. In the Alps, 

 seven fresh paradoxes have already been imagined to justify the one 

 found untenable by itself. 



For more than thirty years I have been familiar with the presence 

 of abundant gypsum, red marls, ophite, and granite in the Cretaceous 

 to the south of Biarritz. The Trias theory rests entirely on their 

 assumed absence. The intrusive granite has this year been exposed 

 by extensive engineering works at St. Jean de Luz. In 1873 I took 

 to Paris a conclusive series of specimens from the same point. Had 

 I then presented them, I should have been boycotted from every 

 society and periodical. I have found similar intrusions abundant in 

 the analogous rocks of Italy, Switzerland, and Greece. But in the 

 Bull. Soc. Geol. of 1902, p. 499, M. Carez again elaborately proves 

 the absence of granite intrusions familiar to me along 200 metres 

 just east of the bridge of Salies du Salat ; and the source of M. Ber- 

 trand's speculations at Biarritz is the fact that he has described as 

 exotic granite, at Lasseube, a common feature of the decomposing 

 diabase of the Pyrenees. Palassou corrected the same blunder in 

 1819. The demand for local accuracy and experience was still active 

 during my apprenticeship, and I owe to it whatever real information 

 I possess. The present ideal is realized by the man who can describe 

 an entire continent where he has never set foot. If any geologist 

 without the taint of local knowledge, or the stigma of repeated 

 success in quashing reckless assertion, would study the abundant 

 literature of the Biarritz problem, he might do much to stem the 

 torrent of garbled compilation that drowns all useful work in the 

 most accessible of European chains. His observations might gain 

 a hearing on the ground that their refutation should be easy. 

 Mine are too well known to be unanswerable, and thereby only 

 describable as polemics. That word, and the prompt substitution of 

 one reckless fallacy for another, appears to console my opponents 

 and satisfy their admirers. P. W. Sttjakt-Mbnteath. 



St. Jean de Luz, Matj 5, 1903. 



p,g. — On the road to Iholdy, at two kilometres south-west of 

 St. Palais, the granite-like ophite, long known at Lasseube, can be 

 seen rising from beneath extensive Upper Cretaceous ; and many 

 similar cases forbid the assumption of superficial carting where the 

 relations are obscure. The nature of the Biarritz problem can be 

 understood from my map in Comptes Bendus de VAcademie des 

 Sciences of June, 1894; 



