1854.] 



HAMILTON MAYENCE BASIN. 



261 



heim, this sand, which is there coarse and shelly, alternates with 

 beds of hard compact limestone, also fossiliferous, although, in such 

 cases, it is almost impossible to extract their contents. A few miles 

 S.W. of Weinheim, between the villages of OfPenheim and Becken- 

 heim, is a good section of this marine sand, overlaid by thin beds 

 of blue and mottled clays, close to the very edge of the basin, as 

 shown in the neighbouring quarry (only a few paces above it) of 

 micaceous sandstone-grit, evidently belonging to the Carboniferous 

 system. The accompanying section, fig. 5, will show the relative 



Fig. 5. — Section of the ''Marine Sands" and " Cyrena Clay." 

 w E. 



Micaceous 

 sandstone. 



|B2. 



3C. Soil. 

 B. 2. Cyrena-clay. 

 B. 1. Marine sands. 



position of these beds. This spot, which had been opened apparently 

 as a sand-pit, offered the following section in descending order : — 



ft. in. 



Upper blue clay, with septaria 4 ■ 



Brown clays 1 



Second band of blue clay I 



Brown clay, with small nodules of phosphate of lime ? . 11 



Ferruginous clay 4 



Lowest blue clay, with traces of vegetable matter .... 9 



Ferruginous clay 4 



Ferruginous sand 3 4 



White sand, with ferruginous streaks 10 



— the latter in fact extending to the bottom of the pit, as far as was 

 exposed, and probably much deeper. It should be observed, that 

 in this pit we found no fossils whatever, nor even a pebble or other 

 extraneous matter. To the E. and S.E. the same beds are seen 

 stretching away from the ancient shore, and increasing in thickness ; 

 and at no great distance we found in a bank by the road-side a 

 section nearly on the same level as the sand-pit, in which the clays 

 abounded with Cerithium margaritaceum, another smaller Cerithium., 

 probably C plicatiim, Cyrena subarata,?a\A. a small Ostrea, proving 

 these clays to be the same as those which near Weinheim and else- 

 where overlie the marine sands, and belong to the lower brown- 

 coal formation or Cyrena-marl of the German geologists. 



The lower or true marine formation extends, or rather has hitherto 

 been observed, only over a small portion of the Mayence district. It 



