1866.] GODWIN-AUSTEN — BELGIAN TERTIARTES. 247 



lations, though somewhat distant, is curious as a coincidence, but in 

 both cases it perhaps may be explained by the inconsiderable thick- 

 ness, as also the loose materials, of the two formations. 



IV. Newer Kainozoic. 



1. Cailloux Ardennais. — In the sections about Antwerp we seldom 

 failed to detect the thin line of quartz pebbles, to which the Belgian 

 geologists have called attention, as underlying the Campine sands. 

 They were here very small, few in number, but perfectly rounded ; 

 they have been derived from the quartz veins of Palseozoic rocks. 

 These are the Cailloux Ardennais of M. Omalius, and came originally 

 from that ridge or axis. As compared with other places to the 

 north and east they have evidently at Antwerp reached their ex- 

 treme limit of dispersion*. 



In the section at Schelle the quartz pebbles serve to separate the 

 Campine sand from the older sandy accumulation ; but for these the 

 line might easily escape detection, so closely do the surface-sands 

 resemble the Crag sands beneath. At this place it is evident that 

 Campine sand has been spread over the country since the denudation 

 of the Crag, as at either end of the section it rests on the surface of 

 the Eupellien clay, and in this position the quartz pebbles are mixed 

 up with the chalk-flints which originally occurred at the base of the 

 Crag, and stiU remain en place. 



About Hasselt the quartz pebbles occur in great abundance and of 

 large size ; with them are chalk-flints, somewhat less water- worn. 

 Towards Maestricht the quartz gravel, as seen in the railway banks, 

 underlies a considerable thickness of argillaceous sand; the accu- 

 mulation increases in thickness as it approaches the line of the 

 valley of the Meuse, ending abruptly at a considerable elevation 

 above the present level of that river, which has deepened its course 

 out of these gravel beds. 



Prom Hasselt towards the Bolderberg the plain presents a con- 

 tinuous spread of siliceous sands, overlying coarse quartz shingle 

 with flints. These sands and gravels end off at the base of the 

 Bolderberg ridge. 



Quartz pebbles, beneath loss, occur in the high ground above Liege 

 on the north, as also north of Namur, both on the surface of the 

 Carboniferous limestone, beneath the loss, as also in the wide 

 fissures of those rocks. Wherever patches of Nummulitic sands 

 occur (Bruxelles beds), the quartz shingle separates the older sands 

 from the loss. 



At Dinant, in the Condroz, the quartz shingle occurs everywhere 

 over the surface on the high ground ; and lastly we met it in the 

 fissures which have been enlarged into the caves of Furfooz. 



These caves occur in a mass of Carboniferous limestone overlook- 

 ing the river Lesse, a tributary of the Meuse, and taking its rise in 

 the high ground of the Ardennes, near St. Hubert. 



* I did not notice any quartz pebbles on the summit of the hill east of 

 Louvain. 



