146 



THE LIAS AMMONITES. 



Gasteropoda. 



Pleurotomaria subdecorata, d^ Orb. 

 Chemnitzia lineata. Sow. 

 *Turbo capitaneus, Munst. 



Trochus duplicatus. Sow. 

 *Natica adducta, Phil. 

 — Oppelensis, I/yc. 



LaMELLIBRANCHI ATA . 



*Lima bellula, var., Lye. ^ Mor. 

 *Modiola plicata, Sow. 

 *Perna rugosa, Munst. 

 *Hinnites abjectus, Phil. 

 *Pecten articulatiis, Goldf. 

 *Gresslya abducta, Phil. 



* — conformis, Agass. 

 Myacites arenacea. Lye. 



*Homomya crassiuscula, Lye. 



Goniomya angulifera. Sow. 

 *Myoconcha crassa. Sow. 

 *Cypricardia cordiformis, Besh. 

 *Pecten comatus, Milnst. 



Opis carinatus, Wright. 



* — lunulatus, Sow. 

 Cypricardia brevis, Wright. 

 Cardium HuUii, Wright. 



— Oppelii, Wright. 

 Cucullsea ferruginea, Lye. 



Terebratala subpunctata, Bav. 

 — trilineata. Young. 



CucuUaea olivseformis, Lye. 

 *Lima electra, d'Orh. 

 Unicardium, nov. sp. 

 Tancredia, noy. sp. 

 Trigonia Ramsayii, Wright. 



* — striata, Sow. 



* — costata, Sow. 

 Pecten textorius, Goldf. 



*Pholadomya fidicula, Sow. 

 — arenacea, Lye. 



Lima ornata, Lye. MS., nov. sp. 

 Astarte lurida. Sow. 



* — excavata. Sow. 



— detrita, Goldf. 



— complanata, Boemer. 



— rugulosa. Lye. 

 Gervillia fornicata, Lye, MS. 



* — Hartmanni, Goldf. 

 Nucula Jurensis, Quenst. 



Brachiopoda. 



Ehynchonella cynocephala, Rich. 

 — Jurensis, Quenst. 



In the above list the species marked with an asterisk are found likewise in the 

 Inferior Oolite ; but the specimens from the sands are nearly all dwarfed forms, showing 

 that the physical conditions under which they lived were unfavorable to their development. 

 The stunted growth of the stationary Lamellibranchs forms a striking contrast to the 

 size, number, and variety of the locomotive Cephalopods interred with them in the same 

 bed ; the dawning existence of the former appears to have been a struggle for life, whilst 

 the conditions under which the Cephalopods existed were favorable to their continuance 

 in time, as shown by the number of species and individuals found in the Erocester beds, ; 

 their life, however, was abruptly brought to a termination by some great physical change 

 which took place about the commencement of the deposition of the Oolitic formations. 



Foreign correlations. — The Jurensis-mergel was first pointed out by Professor 

 Quenstedt ^ as the uppermost member of the " Shwarzer Jura," its importance in 

 1 'Flozgebirge Wiirtembergs,' pp. 267 and 539, 1843. 



