140 



PKOCEEDINGS OP THE GEOLOGICAL SOCIETY. [Jan. 24, 









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elsewhere, ulthougli in their 

 distribution there is something 

 peculiar. The definite separa- 

 tion into zones is rather diffi.- 

 cult. The upper limestones, in 

 which alone Am. angulatus is 

 found, contain a varied fauna, 

 with which there is nothing to 

 compare in the beds below. 

 It is certain, however, that only 

 the lower part of this zone is 

 here exposed. Am. Johnstoni, 

 however, ranges throiigh these 

 and the limestones lower down, 

 and is here the most character- 

 istic Ammonite. The true Am. 

 planorbis has as yet been found 

 only in one bed ; but this is not 

 separated from the others by 

 any other features. The change 

 to the oyster-bands is very 

 marked in pit No. 3,. accom- 

 panied as it is by a cessation 

 of microscopic fossils ; and the 

 same may be said of the change 

 into the white limestone beds 

 below. 



On comparing the " angula- 

 tus " fauna with that of Marton, 

 it will now be seen how nearly 

 allied they are — so much so that 

 it is probable that a com- 

 jdete knowledge of both would 

 prove them to be almost per- 

 fectly identical. As at present 

 known, however, they present 

 some decided differences. Of 

 the 44 species recorded as cer- 

 tain from Marton, 23 are also 

 found at Cliff; and it appears 

 possible that an actual compa- 

 rison of specimens would in- 

 crease this proportion. Pifty- 

 two species are here recorded 

 as certain from the same hori- 

 zon, excluding vertebrates and 

 microscopic fossils; of these 

 15 belong to genera unrepre- 

 sented at Marton. The differ- 

 ence consists chiefly in the 



