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"Rhine-diluvium", wiiich luis a regular gentle upward slope to the 

 south and probably also to the east, and of which rests appear in 

 the low country bounding the plateau to the west, where the "Rhine- 

 diluvium" has been removed. 



There is ]iot much known al)out the total thickness of tlie bed, by 

 reason of the under layer of it ha\ing not yet been attained in any 

 pit. In the Jammerdaalsche Heide the clay is dug out 6 ]M. deep, 

 and it has further been ascertained by means of bore holes, that even 

 2 M. deeper, so at about 19 JM. -|- A. P., the clay makes place for 

 sand. It is however probable that another layer of clay is underlying 

 that sand. In bore holes put do^vn on several places in and about 

 Venlo, some of which approached the last mentioned pit to 27^ K.M., 

 they met with similar clay, in a layer of 8 M. thickness, resting, at 

 4 M. — A.P., on coarse wdiite sand and gravel with much mica, and 

 covered at 4 M. -j- A. P. by 3 M. sand and about 12 M. of graver). 

 Along the right bank of the Meuse, south of A'enlo, the edge of this 

 very ferrugineous and somewhat consolidated gravel appears, coxered 

 by loam, at about 14 M. -|- A.P. Even at very low watermark, of a 

 -few decimeter above 8 M. -f A. P., generally the underlying of the 

 gravel cannot be seen in this outci-op. On a few spots however, 

 about I K.M. south of the Meuse-bridge and 2 K.M. north-west of 

 the mentioned clay-pit, I observed similar clay as that of Tegelen 

 in the original situation, over 7 ^i. in horizontal connection, under 

 the gravel. It I'eaches there upward to 11 M. -\- A.P. Evidently this 

 clay in the bank of the 3Ieuse belongs to the same bed as that which 

 Avas met with in the bore holes at Venlo, the bed having been unevenly 

 eroded a long time before the development of the preseiit river ciiannel. 

 In such a way a difference of 7 M. could arise in the upper sur- 

 face of the clay. In that clay on the right bank of the Meuse I 

 found a tibia of Rhinoceros, which is only assimilable with that l)one 

 of R. etruseii.s and 7i. Mercki. The bone ^vas still a little fastened in 

 the clay, for the greater part enveloped with the consolidated gravel. 

 This clay is thereby characterised as interglacial or preglacial (pre- 

 pleistocene). If belonging to the same bed as the Clay of Tegelen, the 

 whole thickness of the latter, including sandlayers, may be estimated 

 at about 30 M. In this computation it has been supposed that its 

 under surface, from Venlo to Tegelen, is horizontal, which seems 



1) According to a communication of Mr. de Waal Malefijt the top of the clay 

 was 5 M. lower in a bore hole put down on the right Meuse-bank at Venlo. Pro- 

 bably the clay which has been met with in bore holes, 24 K.M. south of Venlo, 

 on the east side of the Meuse in the neighbourhood of Roermond, at about 

 3 M. + A.P., under as much gravel, is geologically identical with that under Venlo. 



