Vol. 58. | SUBALPINE PLIOCENE CONGLOMERATES. 461 
impermeable surface-soil.t It is in that ‘ conglomérat ferrugineux ’ 
of the Dombes that Llephas meridionalis and Mastodon arvern- 
ensis were found by Fontannes,” to whom thus belongs the merit 
of having fixed the Upper Pliocene age of that conglomerate, and 
thereby, although unwittingly, that of the first glaciation of the 
Alps of which that conglomerate is the indirect product —although 
he regarded it as pre-Glacial, and others (for example, A. Falsan 
and EK. Chantre) * classed it with the Quaternary Glacial alluvia. 
Fig. 8.—Section of Alluvion Ancienne across the Dombes plateau, 
from the Sadne to the Rhéne. 
1: 1,250,000 
There are a good many fairly uniform exposures of the con- 
glomerate along the vine-clad slopes of the Sadne and Rhéne 
Valleys, and also in the Valley of the Ain, the conglomerate 
appearing generally about the 300-metre contour, although on the 
diagonal divide of the Rhone and Saéne watersheds, running in a 
line from Lyons to Pont d’Ain, it reaches occasionally the 350- to 400- 
metrecontour. Thesection taken by myself at a point near Fontaines, 
on the leit of the Saéne, about 6 miles north of Lyons, between 
Fontaines and Sathonay (fig.7, p. 460), does not differ materially from 
the section, between Meximieux and the Rhone, given by Delafond.' 
At Lyons itself, the conglomerate reaches to the high-level Croix- 
Rousse quarter in the wedge between the Rhone and the Sadne, 
* The Dombes is often considered as part of the Bresse district : hence Elie 
de Beaumont called the Dombes conglomerate ‘conglomérat bressan.’ The 
Bresse district, north of the Dombes, is, however, a distinct and somewhat 
lower plateau (about the 200-metre contour), much more intersected and 
eroded by watercourses, but otherwise of similar structure and composition, 
the conglomerate being chiefly composed of Vosges material. 
* Bull. Soe. Géol. France, ser. 3, vol. xiii (1884-85) p. 60. 
* ‘Monogr. géol. des Anciens Glaciers’ vol. ii (1880) pp. 65 et seq. 
* Bull. Soc. Géol. France, ser. 3, vol. xv (1886-87) p. 63. 
