236 MIOCENE STRATA OF BELGIUM. [Ch. XIV. 



ions of the Antwerp Crag before mentioned, and contain shells of 

 the genera Oliva, Conus, Ancillaria, Pleuro- 

 Fig. 169. toma, and Cancellaria in abundance. The most 



common shell is an Olive (see fig. 169), called 

 by Nyst Oliva Dufresnii, Bast. ; and consti- 

 tuting, as M, Bosquet observes, a smaller and 

 shorter variety of the Bordeaux species.* 



The Upper Miocene strata in the Bolder- 

 berg occur at the height of about 200 feet 

 owva Dufresnii, Bast, above the level of the sea. They are covered 

 na^ste^' T^lront ^ tlie Diestian sands and iron sandstone 

 view; &,'back'view. already described, and they repose on Lower 

 Miocene beds called Rupelian by Dumont. So 

 far as the shells are known, the proportion of recent species agrees 

 with that in the faluns of Touraine, and the climate must have been 

 warmer than that of the Coralline Crag of Engla#d. 



In none of the Belgium Lower Miocene strata could I find any 

 nummulites ; and M. d'Archiac had previously observed that these 

 foraminifera characterize his " Lower Tertiary Series," as contrasted 

 with the Middle, and may therefore serve as a good test of age in the 

 North of Europe at least, between Eocene and Miocene. The same 

 naturalist informs us that one nummulite only has ever yet been seen 

 to penetrate upwards into the middle tertiary, viz., Nummulites inter- 

 media, an Eocene species. It has been found in the hill of the Su- 

 perga, near Turin, in Miocene beds, somewhat older than the falunian 

 type (see above p. 107). 



North Germany. — We learn from the able treatise published by M. 

 Beyrich, in 1853, that the same fossil fauna, which is so meagrely ex- 

 hibited in the Bolderberg, is rich in species in other localities in North 

 Germany, as in Mecklenburg, Liineburg, the Island Sylt, and at Bersen- 

 bruck, north of Osnahriick, in Westphalia, where it was first observed 

 by F. Romer.f 



Loiver Miocene, Belgium. — It was stated that the Bolderberg beds 

 rests on the Rupelian of Dumont, a Lower Miocene formation best 

 seen at the villages of Rupelmonde and Boom, ten miles south of Ant- 

 werp, on the banks of the Scheldt and near the junction with it of a 

 small stream called the Rupel. A stiff clay abounding in fossils is ex- 

 tensively worked at the above localities for making tiles. It attains a 

 thickness of about 100 feet, and, though very different in age, much 

 resembles in mineral character the " London Clay," containing, like it, 

 septaria or concretions of argillaceous limestone traversed by cracks 

 in the interior, which are filled with calc-spar. The shells, referable 

 to about forty species, have been described by MM. Nyst and De 



* Lyell on Belgian Tertiaries, Quart. Geol. Journ., 1852, p. 295. Nyst's figure 

 seems to be copied from that given by Basterot of the Bordeaux fossil. 



| Beyrich, Die Conchylien der Norddeutschen Tertiargebirge : Berlin, 1853. 



