56 * GEOLOGY. 



soils occupying 7722 square miles. ** The sources and the nature of 

 the rivers vary according to the geological character of the district : 

 thus, when the soil is impermeable (as, for instance, the granite of 

 Morvan, the lias of Auxois, and the clay of Champagne), the streams 

 are numerous but small, and, as the water runs quickly off the surface, 

 the streams and rivers swell rapidly in time of rain, forming torrents, 

 the beds of which are generally dry in summer; in permeable soil, 

 such as the oolitic limestone of Burgundy, the white chalk of Nor- 

 mandy, and the sands of Eontainebleau, the streams rise in the marshy 

 meadows of deep valleys, the springs are considerable and are fre- 

 quently found at the junction of permeable with impermeable strata, 

 the rivers are few, not generally liable to dry up, and their course is 

 gentle. The hardest water comes from the limestones. Lias, and gyp- 

 siferous strata. The water-supply of Paris is obtained from the Dhuis 

 and 'the Yanne." (Proc. Inst. Civ. Eng. vol. xxxix. p. 365.) 



Delitsch, 0. Aus den franzosischen Gebirgen. I. Eine Wanderung 

 im Cantal. [Ajourneyin Cantal.] Aus alien Welttheilen, pp. 236- 



238, 268-270. 



Deshayes, Y. Sur le gisement de Cuivre du Charrier pres la Prugne 



(Allier). [Copper- deposits near La Prugne.] Eull. Soc. Gcol. 



France, 3 ser. t. i. pp. 504-514, pi. xi. 



The ore is Phillipsite in a vein very similar in its associated rocks to 



those of Monte Catini. The rock of the country is granitoid porphyry, 



and the vein-stuff is chiefly serpentinous. The direction of the lode is 



generally N. and S. The average ore yields from 8 to 20 per cent, of 



copper. G. A. L. 



D:fisoR, E. Die Moranen-Landschaft. [Moraine-scenery.] Yerh. 



Schweiz. naturf. GeseU., 1 map. 

 The map is of the district of Amsolderungen near Thun, on a scale 

 of 1 : 25,000. 



Dewalque, G. Sur I'extension verticale de quelques fossiles devonicns 

 reputes caracteristiques. [Yertical range of some reputed De- 

 vonian fossils.] Ann. Soc. Geol. Belg. t. i.. Bull. pp. Ixii, Ixiii. 

 Spirifer distinctus, Sow. {8. Verneuili, Murch.) supposed to be cha- 

 racteristic of the Upper Devonian, has been found near the base of the 

 Eifelicm or Middle Devonian. 



lleceptacuUtes Neptuni, Defr., has a like range. Stringocephalus 

 Burtini, Defr., considered to be characteristic of the Givet Limestone, 

 ranges below to the Couvin schists and limestones. Pleurodyctium 

 problcmaticum, Defr., ranges from the Cohlencian series, of which it has 

 been looked upon as characteristic, probably to the Calceola schists. 



G. A. L. 



Sur le parallelisme des terrains ardennais et cambrien. 



[Parallelism of the Ardennais and Cambrian series.] Ann. Soc. 

 Geol. Belg. t. i., BuU. pp. Ixiii, Ixiv. 



