Ch. XIV.] UPPER MIOCENE OF BELGIUM. 235 



of hills stretching from Diest by Louvain and westward by Oudenarde 

 to Cass el in French Flanders, where they are seen at the summit of a 

 hill 515 feet high. After having been thus traced for a hundred 

 miles from east to west, they are again seen retaining the same mineral 

 character for another hundred miles in a similar westward direction, 

 first capping the Downs near Folkestone, and then appearing at vari- 

 ous points, such as Paddlesworth, Lenham near Maidstone, and Vigo 

 Hill near Otford in Kent. 



The geological position of these iron sands in England was first 

 made out by Mr. Prestwich, who, in a paper read to the Geological 

 Society of London in 1857, described them as being possibly older 

 than the Coralline Crag, and as occurring on the summit of the North 

 Downs at various points between Folkestone and Dorking. He men- 

 tioned their resemblance to the sands at Diest in Belgium, and that 

 they contained the Terebratula grandis, and casts of Astarte pyrula, 

 Emarginula, and otler fossils, all common to the British Crag. After 

 the publication of Mr. Prestwich's paper, I visited with him the prin- 

 cipal localities in Kent to which he had called attention, and saw the 

 ferruginous sands, twenty feet thick, resting on the chalk near the edge 

 of the escarpment, about a mile N.E. of Folkestone, and again at Pad- 

 dlesworth, on the summit of the Downs, four miles W.N.W. of Folke- 

 stone, where the sands are about forty feet thick, and where they occur 

 at an elevation of about 500 feet above the sea. At Lenham, ten miles 

 east of Maidstone, fragments of the more consolidated ferruginous 

 layers, full of casts of marine shells and other fossils, are preserved in 

 vertical sandpipes, which penetrate the white chalk. Here I saw or- 

 ganic remains, reminding me of those which I had seen in 1850. at 

 Kesseloo, near Louvain, in the " Diest Sands," which there overlie the 

 Limbing or Lower Miocene beds.* The evidence, both in Belgium 

 and in Kent, being derived from casts, consists mainly in the corre- 

 spondence of genera ; but some of the species, such as the large Tere- 

 bratula and a Turbinolia, seem identical. 



We cannot determine at present, in consequence of the dearth of 

 fossils in the Diest sands, their exact relation to the Edeghem beds, 

 or whether they may be intermediate between the Edeghem and Bol- 

 derberg strata, but we may at least affirm that the only British strata 

 at present known which can have any claim to be regarded as Upper 

 Miocene are the ferruginous sands of the North Downs here alluded 

 to. 



Upper Miocene of the Bolderberg in Belgium. — In a small hill or 

 ridge called the Bolderberg, which I visited in 1851, situated near 

 Hasselt, about forty miles E.N.E. of Brussels, strata of sand and gravel 

 occur, to which M. Dumont first called attention as appearing to con- 

 stitute a northern representative of the faluns of Touraine. On the 

 whole they are very distinct in their fossils from the two upper divis- 



* See a Memoir by V. Pvaulin, 1848 : Bordeaux. 



