1854. 



HAMILTON MAYENCE BASIN. 



263 



in thickness, in which the greatest number of shells is found ; the 

 lower portion in particular is almost a complete mass of such remains. 



Fig. 6. — Section of the "Marine Sands" (B. 1), near Weinheim ; 

 opposite the Wirthsmiihle. Height of Section about 20 feet. 



Trap- rock. 



6. Gravel. 



5. Calcareous sand ; Pectunculus, abundant. 



4. Shelly sand. (At about this level on the opposite side of the valley, the Cyprina rotundata 



occurs ; fig. 7.) 

 3. Hard-bedded limestone ; Pectunculus crassus, &c. 

 2. Shelly sand ; Natica gigantea, &c. 

 1. Compact limestone. Few OstretE. 



many of which are broken, while others have their valves pierced by 

 borers, showing that they were probably already dead before they 

 were washed into this locahty. Those in the upper portion are 

 better preserved. 



This shelly sand is again overlaid by a compact hard calcareous 

 sandstone, in which the large Pectunculus crassus (Phil.) is very 

 abundant ; this passes into a softer arenaceous bed, in which the 

 Pectunculi, in consequence of the denudation of the intervenino- 

 strata, are in immediate contact with the diluvial gravel. 



The section, fig. 7, represents the beds as seen in the hollow-road. 



Fig. 7 — Section of the Alternations of Sandy and Calcareous beds 

 in the "Marine Sands," B. 1, at the Hollow Way behind Wein- 

 heim. 



9. Sandy ; PeclunciUus, very abundant. 



8. Calcareous. 



/. Shelly sand. 



6. Calcareous. 



5. Sandy ; Cijprina rotundata. 



4. Calcareous. 



3. Loose sand. 



2. Calcareous. Halianassa bones. 



1. Sandy. 



or pass, behind or to the north of the same hill, at a somewhat higher 

 level. The fossil remains found here are generally the same as those 



VOL. X. — PART I. U 



