Four articles in the Biarritz Association Bulletin, and a series in the last publications of the Soc. Géol. de Fiance, discuss the problem of Pyrenean ophite by conjectures regarding the obscure points of greenstone in the shifting sands of the Biarritz coast. When first seeking new facts at Biarritz, I discovered the red marls and gypsum that accompany the ophite to be recurrent in the undisputed Upper Cretaceous of Croix d'Ahetze, and I followed the Biarritz rocks to Zumaya and Loyola in the attempt to trace their relations. Having subsequently proved that the other red clays mapped as Trias are brick clay of post-Glacial origin, contemporary with a tooth of Elephas primigenius and anterior to flint implements described as Pliocene, and having vainly demonstrated the continuity of the rocks of the Spanish coast by both maps and fossils, I would invite geologists to profit by the light railways and other advantages which to-day enable the fundamental section of Pyrenean geology to be easily studied in its unmistakable continuation.