Nov. II, 1875] 



NATURE 



31 



then, too, the joint processes are wanting, &c. On the 

 other hand, Geotriton is distinguished in the most 

 peculiar way, by one organ, from all other Amphibia, viz., 

 by the tongue. This is a pedicelled disc, like a mush- 

 room, on the bottom of the mouth cavity, where it is con- 

 nected with the tongue-bone apparatus ; the latter, how- 

 ever, does not merely consist of the same parts as in 

 other Amphibia, but at its two hinder ends there is 

 attached on either side a long thin cartilage, which 

 reaches, free between the neck muscles and the skin, as 



far as the back, and is enclosed in an envelope of special 

 muscles, which are only attached at its hinder end and in 

 front to the rest of the tongue-bone. If, now, this muscle 

 be contracted, it thrusts out the cartilage rod, and with it 

 the tongue, in a way similar to that observed in Chame- 

 leons, Woodpeckers, and Ant-eaters. Compare the annexed 

 drawing. Thus Nature connects in the most remarkable 

 manner a complicated organ of the higher Vertebrates 

 with the organisation of amphibians that evidently stand 

 very low. 



EVIDENCES OF ANCIENT GLACIERS IN 

 CENTRAL FRANCE 



WHEN visiting the Mont' Dore district, in Central 

 France, with Prof. Huxley in the summer of 1873, 

 my attention was accidentally directed to some magnifi- 

 cent transported boulders occupying the floor of an ele- 



vated valley due south of the highest ridge of the Pic de 

 Sancy. 



These, though gigantic, and occupying a very con- 

 spicuous position, in every respect similar to positions 

 occupied by deposits from ancient glaciers in Switzerland 

 and in all other Alpine regions, are not alluded to in Le 

 Coq's exhaustive work on Central France, or his geolo- 



:^^^ij^ .1 ■■ 



Fig. I. — Transported blocks in ]the Trsmteine Vallef, Mont Dore. Mountains of Cantal in the distance. 



gical map appended thereto ; nor are they in either of 

 Mr. Scrope's works on the Volcanoes of Central France ; 

 nor can I obtain any information regarding them from 

 those of my geological friends who are most versed in 

 glacial phenomena. 



Under these circumstances, though still of opinion that 



they cannot have escaped the notice of French observers, 

 if not writers, on the geology of France, I may assume 

 that they are of sufficient novelty and interest to render 

 the accompanying notes and sketches acceptable to the 

 readers of Nature. 

 The well-known lofty range of Mont Dore is described 



Fig. 2.— Transported block in the Tranteine Valley, Mont Dore (estimated length 36 feet). Pic de Sancy (N.) in the disunce 



'by Scrope (" Volcanoes," ed. ii., p. 362) as a mountain 

 mass rising in its highest peaks more than 6,200 feet 

 above the sea-level, composed of beds of trachytic and 

 basaltic lavas, alternating with their respective conglo- 

 merates. And again, in his " Volcanoes of Central 



France" (ed. ii., p. 124), the same author says oi the 

 figure of the mass, that it is best understood by supposing 

 seven or eight rocky summits grouped together within a 

 circuit of about a mile in diameter, from which, as from 

 the apex of a flattened and somewhat irregular cone, all 



