414 PUR BECK BEDS AND IRON-SAND. CHAP. 



Thus above 60 feet are assigned to the group of iron-sands. It 

 is in the lower group, which also contains ochre, that the shells 

 occur which were first noticed by Mr. Jelly. He found them about 

 30 feet above the Portland rocks ; but my observations lead to the 

 conclusion that they occur in all parts of the deposit, from the very 

 base to nearly the top of the hill. They have, however, never been 

 seen by me in the very uppermost sandstones, about 20 feet thick. 



In the uppermost layer, at the east end of the -great pit on the 

 north-eastern slope, which is really pisolitic or oolitic iron ore, half 

 decomposed into ochre, I observe a few traces of what seem to be 

 organic forms, but as yet nothing definite has been recognized. 

 That pit, when in full work some years ago, presented the following 

 section of beds, which probably are the highest of the series : 



ft. in. 

 Ferruginous sandstone formed in irregular beds, with irony joints 



and concretions, part of it a true iron ore . . . .120 



Blue, pale, laminated, sandy clay 30 



Yellow sand, laminated, the upper surface irregular . . .30 

 Pale yellow and white stripy sand . . . . 2 o to 3 o 

 Blue clay, with brown band of clay at the bottom . . .10 



Yellow, pale brown sands 4 o 



Pale blue sandy clay 12 



Pale laminated sand . . . 02 



Pale sandy clay . . . . . . . . . .010 



Yellow, white, and reddened sands 4 o 



Blue clay 03 



Yellow ochre of good quality 03 



The layers of these cherts, sandstones, geodes, clays, loam, and 

 ochre are very irregular in extent and thickness, yet not in such a 

 way as to suggest more than gentle current-action. There is 'very 

 little false-bedding ; the layers are mostly undulated, and the con- 

 cretionary tendency of the oxide of iron has produced ramifying 

 and geodic masses much harder than the rest. The shells are now 

 almost confined to these hard irony masses, perhaps because there 

 only preserved from destructive solutions. The white sands and 

 white clays are in continuous deposits, the latter in very thin 

 laminae. 



The organic remains hitherto found in the upper sands of Shot- 

 over, and especially in the irony parts of the deposit, consist of 



Coniferous wood in fragments. A small coniferous stem. Leaf of Pecopteris. 

 CRUSTACEA. 



Cypris ? It seems to be recognized in some of the minute hollows which abound 



