526 



J. F. BLAKE ON THE UPPEE 



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Our first traverse is down the valley 

 of the Aube, on either side of Bar-sur- 

 Aube. At Clairvaux, not very far north 

 of Maranville, near the river, there 

 are great cement-works, where cement- 

 stones, more or less sandy, and inter- 

 spersed with marly beds, are worked over 

 a thickness of 40 feet or more. These 

 contain abundant fossils ; the chief noted 

 were Ceritliium muricatum, Pholaclomya 

 canaliculata, P. cingulata, Trigonia per- 

 lata, Anatina magnified, Goniomya sul- 

 cata, Pinna lanceolata, Gervillia avicu- 

 loicles, and Exogyra spiralis. There really 

 cannot be very much doubt whereabouts 

 we are in the series here ; it must be 

 the top of the Oxfordian, somewhere on 

 the level of the Lower Calcareous Grit. 

 These, in fact, appear to be the beds that 

 are missing a little further to the east 

 (at Buxieres), and probably on a higher 

 horizon than those at Maranville. In 

 any case the fauna is perfectly distinct 

 from that of the somewhat marly lime- 

 stones which lie above the Diceras-beds 

 at Youecourt. In Leymerie's lists no 

 such assemblage is noticed ; and it would 

 seem that these beds were not open to 

 his observation. 



The immediately overlying rocks are 

 not well observable here ; but there ap- 

 pears no sign of rubbly Coral Rag or of 

 Diceras-beds, in place of which the 

 marly beds become more sandy, then 

 more solid, and finally change into a 

 massive limestone. This is not to be 

 wondered at, when w T e observe the great 

 reduction the Diceras-beds have suffered 

 between Buxieres and La Mothe. We 

 are here introduced, in fact, to the fea- 

 ture which characterizes much of the 

 western extension of the Upper Jurassic 

 rocks : they tend more and more to be- 

 come a uniform mass in which recog- 

 nizable rocks of peculiar constitution 

 are mere occasional occurrences. The 

 solidity of the limestones in this dis- 

 trict is well shown in a quarry-face 

 of 60 feet, the base of which is reached 

 by a continual ascent through a stony 



