394 SCIENCE PROGRESS 



in places and sometimes gritty, with softer bands, fairly rich in 

 fossils. At 1,287 t0 1,289 ft. there is a thin band of dark purplish 

 slicken-sided clay; at 1,290 ft. a poorly oolitic marl, with 

 lignite, shell remains, and a big coral. At 1,293 ft. is a highly 

 fossiliferous band, with crystalline calcite and numerous casts of 

 shells and corals. The texture is generally medium oolitic, in 

 places barren, in others richly fossiliferous. From 1,345 ft. to 

 1,351 ft. 6 in. we find only a washed sandy clay, which probably 

 marks the base of the Bathonian. 



? Lias (1,351 ft. 6 in. to 1,375 ft. 6 in.). 



It is with much doubt that these twenty-four feet of marlstone 

 are provisionally referred to the Lias. At the top we have a fine 

 grey calcareous sandstone, rich in shell remains, passing into an 

 arenaceous limestone, with belemnites, then again to a compact 

 blue limestone full of Rhynchonella : with a marl parting at 

 1,367 ft. 6 in. ; at 1,369 ft. it is a fine sandy dark grey marl- 

 stone with Rhynchonella and casts of bivalves, which becomes 

 tougher, more compact and more calcareous. At 1,371 ft. 4 in. 

 there is a dark grey laminated shaly clay, with a few inches 

 of clayey wash ; finally a laminated silty clay, with a small 

 belemnite, recalling B. acutus, resting directly on the Coal 

 Measures, with no distinct basement bed. 



There are several curious features about this section : we 

 may specially note the disappearance of the Hythe Beds and 

 of the Kimmeridge Clay, the characteristic green rock, and the 

 occurrence of the millet-seed ironstone in the Corallian and 

 Cornbrash (?). At Dover it occurred in the Corallian. 



A detailed account of the Ropersole section has not been 

 published, but it is possible to obtain a fairly clear idea of the 

 structure of the mesozoic rocks at the boring by comparing the 

 journal with the section at Fredville. On this somewhat unsatis- 

 factory basis, we can provisionally establish the following 

 section : it should be noted that the type of Fredville is repre- 

 sented rather than that of Dover, in the disappearance of the 

 Kimmeridge clay as well as of the Hythe Bed, and the presence 

 of the green (?) Cornbrash. 



Chalk (834 ft.). 

 Thickness. Depth. 



350 ft. Chalk with many flints (Upper Chalk) .... 



160 „ Chalk with few flints (probably Middle Chalk) . 



Zone of Terebratulina gracilis, part of Rhynchonella 



cuvieri ... 



