332 CONDITIONS OF DEPOSITION 



overling fine-grained beds, leads to the same conclu- 

 sion. 



The shelly limestones also contain the stronger shells 

 in a perfect state ; some of the weak shells, such as 

 Inoceramus, that break up into small fragments of pe- 

 culiar shape, can be recognised in these beds, but they 

 are only found complete or nearly so in the fine-grained 

 beds. The shelly limestones seem to have been formed 

 in shallow water, for most of the shells were rolled 

 about, broken, and had the projecting points rubbed off 

 their outer surfaces before they came to rest and were 

 buried under the accumulating sediments. 



The fine-grained sandy calcareous clays contain strong 

 and delicate shells in an excellent state of preservation. 

 These beds were laid down in quieter water than the 

 shelly limestones, and in consequence the most delicate 

 shells were buried under the sand and mud without 

 being broken. Over thirty species of Foraminifera and 

 Ostracods have been found by Mr. Chapman in some 

 small lumps of the rock that were sent to him for 

 examination. 



The lowest bed in the section given on a previous 

 page is the most persistent of the whole series. The 

 rest of the rocks are separated into many beds by the 

 thin lenticular shelly limestones in such a way that 

 two sections measured about a hundred yards apart 

 would not show precisely the same arrangement of beds. 

 This group of rocks was formed near the shore of a sea 

 teeming with life ; the shelly limestones were deposited 

 where strong currents prevailed, for a certain period, 

 over a comparatively small area, which were replaced 



