462 



Mr. Horner on the Geology of the Environs of Bonti^, 



The following are the shells which I have found in it in this district : they 

 were named by Professor Goldfuss. Helix pomatia, H. nemoralis Linn., 

 H. arbustorum Linn., H. hispida Linn., //. pulchella Drap., H. incarnata 

 Drap., H. glabella Pfeiff., Lymneus minutus Drap., Pupa muscorum Linn., 

 P. unidentata Pfeiff., Bulimus radiatus Drap., Clausilia obtusa Pfeiff*. 



Bones of Elephas primigenius and Rhinoceros tichorhinus have been found 

 in the loess which covers the basalt in the Unkel quarry. In that near 

 Lannesdorf I found a fragment of a rib belonging to an animal of the size of 

 a horse or ox, and I obtained from the neighbourhood of Ober Dollendorf a 

 few bones, which upon showing to my friend Dr. Miiller, Professor of Ana- 

 tomy at Berlin, he considered to belong to the lower jaw of a young individual 

 of a species of deer. 



It is remarkable that such a deposit should be almost devoid of all vegetable 

 remains. They are not noticed by Professor Bronn and other writers, and I 

 have never found any*. 



Vallei/ of the Rhine. 



The Rhine, from Linz downwards, flows through a deep deposit of gravel, 

 with the exception of about three miles on the left bank, between Remagen 

 and Rolandseck, where the hills come nearly to the water's edge, and the 

 grauwacke strata appear in the side and channel of the river. The gravel is 

 composed for the most part of grauwacke and quartz, but the former predo- 

 minates. It is very distinct in its character from that which covers the brown- 

 coal beds on both sides of the river, in which quartz is the prevailing material, 

 and which is usually of a bright yellow colour, from an admixture of oxide of 

 iron, which I have never found to be the case in the gravel of the plain, deep 

 sections of which are shown in pits in several places distant from the river. It 

 is of an unknown depth; wells which have been sunk sixty feet have not 

 passed through itf . 



The plain which spreads out on both sides from the gorge near Rolandseck, 

 has by no means an uniform flat surface ; there are long low ridges in the 

 direction of the stream, but not parallel to its present bed, which seem to indi- 

 cate that the Rhine, previous to the historical epoch, had occupied a different 

 channel from that in which it now flows : that at one time its course was very 

 near the foot of the ridge from Ober Cassel to Kiidinghoven, and at another 

 time close under the brown-coal plateau on the left bank, westward of Bonn. 

 The situation of Cologne, founded in the early part of the first century, proves 

 that it has flowed in its present course for at least eighteen hundred years. 



* See Appendix VIII. p. 474. t See Appendix IX. p. 478. 



