JURASSIC OF THE PAEIS BASIN!. 



521 



hill-road. The base of the hill called " Les Lavieres " is formed by 

 well-exposed sandy marls and flaggy beds, which are very poorly 

 fossiliferous, and appear to represent the " marls without fossils," 

 the only fossils obtained being Amm. marantianus and Area rhom- 

 boidalis, the latter a fossil of wide range. The amount of this 

 material must be considerable ; in fact, in the neighbouring cutting 

 of Buxieres about 50 feet is seen. Above these marls, on the road 

 running north, are quarries of rock somewhat slipped out of place, 

 but consisting of solid blocks of true oolites with Amm. plicatilis — 

 a very good representative of a " coralline oolite." Soon a river- 

 cliff is reached, by the side of which the road runs, and we have 

 a continuous section with scarcely a break. First there is a shell- 

 limestone, in parts oolitic, containing Chemnitzia heddingtonensis, 

 Neritopsis Guerrei, Cerithium inornatum, Nerincea sp., Trigonia Etal- 

 loni'l, Lima Icevvuscula, Pecten articidatus, Ostrea solitaria, PhyncJio- 

 nella corallina '?, JR. pinguis, and Terebratula rotundata ?. There are 

 also numerous corals ; in fact, in places towards the upper part the 

 rock becomes a complete reef: but the corals are not commonly 

 Thamnastraean, and the urchin is 0. SmitJiii and not C. florigemma. 

 Nevertheless these coral-growths must represent the Eag ; for, traced 

 upwards, the rocks become more oolitic, then pisolitic, and finally, 

 without our being able to draw any line, we are fairly launched into 

 the characteristic Diceras-beds with all their great masses of rubble, 

 their Diceras and Cardium corallinum. The whole of these beds 

 constitute a magnificent assemblage of limestones which can scarcely 

 be less than 300 feet in thickness. There is no change here in a 

 horizontal direction, as stated by Tombeck. The beds dip slightly to 

 the north, which brings higher beds to the same level; but the 

 Diceras-beds are not met with till we begin to mount ; it is there- 

 fore, on the contrary, a vertical succession. The beds which overlie 

 the Diceras-beds here gradually lose their pisolitic character and 

 become marly and rubbly, but are often compacted into solid blocks. 

 The fossils observed in these beds were PJwladomya Protei, Ceromya 

 striata, Mytilus perplicatus, Trichites sp., Ostrea gregaria, and Tere- 

 bratula Leymerii. These beds represent, apparently, the subdivisions 

 C to F of Tombeck's first zone of Ter. humeralis, and have a thickness 

 of about 60 feet. They are here followed by a somewhat more oolitic 

 block capped with a bed of RhyncTionella pinguis, which may well 

 be the continuation of the block quarried at Saucourt. Above this 

 come compact, nearly lithographic limestones, which occupy all 

 the summits of the hills. The whole succession is here therefore 

 perfectly clear, and it is singularly like what has been recorded as 

 seen at Eeynel. 



There is nothing in all this to indicate any thing abnormal, fur- 

 ther than the characteristic inconstancy of the Corallian rocks. The 

 Oxfordian strata, however, appear to have put on a different facies. 

 There is here no Calcareous Grit with characteristic fossils, nor any 

 Ferruginous Oolite ; and the species of Ammonites are not those which 

 are common to the east. Further down in the Oxford clay the zones 

 appear to be continuous, and hence the new form of marls with 



