ZONE OF AMMONITES MARGARITATUS. 



83 



upper, a rock-bed of an impure limestone, weathering blue or brown in tlic interior. In 

 the eastern part of the district it is highly ferruginous, and varies from one to ten feet in 

 thickness. The rock-bed forms the surface of the tabulated ])romontories which produce 

 such picturesque features along the flanks of the Cotteswold Hills, and around many of the 

 outliers, while the steep, fertile banks which descend from the edges of the platforms to 

 the Lower Lias plain are composed of the underlying beds of sand. 



At Leckhampton Hill the thickness of this formation is 115 feet, and this is its 

 estimated general thickness around the Cotteswold Hills. The zone of Ammonites spinatus 

 is so closely incorporated with the Marlstone rock-bed that it must be included in this 

 stage, of which it forms the uppermost portion. 



Fossils from the Marlstone. 



Yertcbrac of Iclitlivosaurus. 



Vertebrata, 



Teeth and scales of fishes. 



Belemnites compressus, Staid. 



— paxillosiis, Schloth. 



Nautihis striatus. Sow. 



— intermedius, Sow. 



Cephalopoda. 



Ammonites margaritatus, Montf. 

 Englehardti, dCOrhig. 

 — Normanianus, (TOrbig. 

 ■ — heteropbyllus amalthei, Quenst. 



Plpnrotomaria Anglica, Sow. 



— undosns, Schiihl. 



— ■ expansa, Sov). 



Gasteropoda. 



Chemnitzia undulata, Zlet. 

 Turbo orion, (TOrbig. 

 Trochus imbricatns, Sow. 



CONCHIFERA. 



Pholadomya ambigua, Sow. 

 Pleuromya unioides, Rom. 

 - — rotundata, Golrlf. 



— Alduini, Brong. 



— donaciforme, Goldf. 

 Ceromya lineata. Will. 

 Areomya elongata, R'Om. 

 Unicardium cardioides, Phil. 

 Cardiuni truncatum, Phil. 

 Cardinia crassiuscula, Sow. 



— crassissima, Sovj. 

 Gouiomya capricorni, Wr. 



Cypvicardia ciicuilata, Goldf. 

 Modiola scalprum, Sow. 

 Limea acuticosta, Goldf. 

 Monotis insequivalvis, Soiv. 

 Lima Hermanni, Voltz. 



— duplicata, Sow. 



— pectinoides, Sow. 

 Pecten diversus. Buck. 



— cequivalvis, Sow. 



— cinctus, Sow. 

 Gryphsca gigantea, Sow. 

 Ostrea. 



