264 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 22, 



near the Wirthsmuhle, but tbere is a more frequent alternation of 

 soft shelly arenaceous, and hard compact areno-calcareous beds ; we 

 observed as many as four or five of these alternations. In the 

 lowest of them, Mr. Austen found some fossil bones, but which, 

 from the extreme hardness of the rock, it was impossible to 

 extract. They belonged in all probability to the Halianassa Collinii, 

 the remains of which are found not unfrequently in this lowest 

 marine bed. 



The remains of Mollusca were most abundant in the two upper 

 beds, Pectunculus arcattis and P. crassus particularly abounding in 

 the uppermost. The large Cyprina rotundata occurs chiefly in the 

 sand below, in which few other fossils were found. The limestone- 

 bed below the Cyprina-sand does not run continuously along the 

 face of the scarp, but occurs in the shape of large nodules, which, 

 from their greater resistance to the weathering action of the air and 

 rain, project beyond the softer sands like the gigantic rafters of a 

 building. 



On the opposite or northern side of the red-sandstone ridge which 

 separates the valley of Alzeyfrom that of Flonheim to the N.E., the 

 marine sands are seen in considerable thickness near Flonheim and 

 Uffhofen, as has been already observed. Near Flonheim they are 

 seen resting on the red sandstone in a sand-pit a little way above the 

 town. The sand here contains but few fossils, and evidently repre- 

 sents a sandy beach along an open line of coast. Section fig. 2, 

 page 258, will give an idea of this character. A depth of from 30 to 

 40 feet is exposed in the sand-pit, but they have dug 15 feet lower 

 through the sand. The lowest portion («) consists of a gravel of 

 small quartz-pebbles, like that seen near Eckelsheim. (b) represents 

 an Oyster-bed, amongst which Shark' s-teeth are not unfrequently 

 found ; these latter indeed occur generally throughout every portion 

 of this section. At (c) is the stratum in which bones have been fre- 

 quently found, and on the occasion of my last visit I succeeded in 

 extracting one, apparently a rib of Halianassa. 



At Uffhofen are sand-pits of the same character and at nearly the 

 same level, abomiding in Ostrea Collinii, which form in the lower 

 portion regular thick banks ; many of these Oysters are covered 

 with large Balani. Here, a few days before my last visit (July 

 1853), a most interesting and entire skeleton had been discovered 

 imbedded in the soft incoherent sand, and was still \jvag as it had 

 been found when we visited the spot. The lower jaw, and upwards 

 of thirty vertebrae with their ribs, some slightly broken, were 

 lying almost in their true position. The upper jaw and skull, 

 having been found a short time before, had been sold to a neigh- 

 bouring collector ; the sand-digger, who found them, never dreaming 

 that the remaining portions of the skeleton were then so near. From 

 the short examination which Dr. G. Sandberger and myself could 

 give them, there is little doubt but that they belong to the Halia- 

 nassa Collinii, of which it is the most perfect specimen yet found*. 



* I have since learned that this fine specimen has been secured by Prof. Kaup 

 for the Museum at Darmstadt. 



