412 PUEBEGK BEDS AND IRON-SAND. CHAP. 



Hill; but we found no shells in the iron-sands, nor did it then 

 appear that my friend had much expectation of adding to the facts 

 he had already communicated. He must, however, during the 

 period between 1847 an( l 1 %54 nave been more successful; for I 

 find in the Oxford Museum a remarkable specimen of Unio, which 

 he discovered not far from the summit of the hill ; and it is known 

 that, in explaining to his class the geology of the vicinity of Oxford, 

 he insisted on the probable fresh-water origin of the Shotover sands, 

 and even traced out in imagination the course of the river-action 

 to which they were due. 



In 1854 I first conducted my class to Shotover, and engaged 

 thirty or forty busy hands to renew the search in the iron-sands. 

 We were more successful than our predecessors, and have on this 

 and subsequent occasions gathered a few Conchifera and Gasteropoda, 

 and plenty of coniferous wood. What seem to be cavities left by 

 Cypridae also occur, among other hollows due to a different cause, 

 in the ferruginous portion of the thick mass of sands and their 

 clays which overlie the Portland rocks; but I cannot say their 

 recognition is certain. 



In ascending Shotover from Oxford we meet (see sections, Plate 

 XVI, figs, i and 2) 



A. The Oxford clay, with its usual characters. This deposit has 

 been penetrated, by a boring for water at St. Clement's, to a 

 depth of 400 feet. (Add 70 for the higher beds up to the 

 calcareous grit.) The lower parts, which are seen but rarely 

 in the Oxford district, yield Ammonites Duncani; the upper 

 parts, Ammonites vertebralis. Gryphsea dilatata appears in the 

 upper half; and bones of Plesiosaurus occur both in the upper 

 and the lower parts. 



B. Calc-grit, or sands with cherty and shelly bands, containing the 

 usual fossils Pinna, Ammonites vertebralis, &c. 



C. Coralline oolite, with shelly rag-beds. In this tract the oolite 

 is superior, the shelly rag inferior. 



Isastraea. Pecten laevis, &c. 



Cidaris. Belemnites abbreviatus. 



Nucleolites. Ammonites catena. 

 Clypeus. perarmatus. 



Lima. Chemnitzia. 



Ostrea gregarea. Turbo, &c. 



The top of the rock is waterworn. 



