578 STRATIGRAPHICAL GEOLOGY 



Staple Hill there is a bed of pebbles and stones overlain by some 

 thickness of sand dipping steeply toward the east (see Fig. 193). 4 



The lignites are described by Pengelly and Heer as consisting 

 mainly of Sequoia wood and the compressed fronds of Osmunda 

 lignitum. The leaves and seeds of the following plants are also 

 common : Nyssa, a tree now living in the southern United States ; 

 Quercus Lyelli (an evergreen oak), Cinnamomum (two species), Vitis 

 teutonica and several other species, Palmacites (the prickly cactus), 

 and the water plants Stratiotes Websteri and Potamogeton tenuispina. 



D. CONTINENTAL MIOCENE 



1. France (Aquitaine) 



Aquitanian. The. typical Aquitanian is found in the near 

 Bordeaux, 5 and the typical marine fauna of this stage occurs in the 

 " faluns " or calcareous shelly sands of Bazas and Lariez, some of 

 the commoner species being Ostrea aginensis, Area cardiiformis, 

 Turritella Desmaresti, Protoma Basteroti, Neritina Ferussaci, 

 Cerithium calculosum, C. fallax, Melongena Lainei, M. cornuta, 

 Oliva clavula, and Nassa aquitanica. 



These beds are overlain by a freshwater limestone containing 

 Helix Morognesi and Planorbis Mantelli ; this " calcaire gris de 

 1'Agenais " must not be confounded with the " calcaire blanc de 

 1'Agenais," which forms the top of the Oligocene, and is character- 

 ised by Helix Ramondi and Cyclostoma antiquum (see p. 566). 



Burdigalian. The typical Burdigalian fauna is that of Leognan ; 

 some of the characteristic species are Turritella terebralis, Protoma 

 cathedralis, Tudicla rusticula, Pecten burdigalensis, Clypeaster margi- 

 natus, and Scutella subrotunda. On the Sancats horizon Agaronia 

 ( = Oliva) Basteroti and Dorsanum baccatum are common shells. 



Helvetian. The faluns of Salles furnish another fauna in 

 which figure Valuta (Scaphella) Lamberti, Cassidea saburon, Pecten 

 solarium, P. scabrellus, Gardita Jouanneti, and Panopcea Menardi. 

 Eastward these marine sands pass into a freshwater formation, the 

 molasse of Armagnac, consisting of marls of various colours (yellow, 

 green, and red), limestones and calcareous sandstones, the whole 

 said to be 1000 feet thick. The lower beds yield bones of Mastodon 

 angustidens, Rhinoceros sansannensis, and Amphicyon major ; the 

 upper beds those of Mastodon tapiroides, Dinotherium giganteum, 

 and Anchitherium aurelianense. 



2. Orle'anais and Touraine 



Aquitanian. The deposits of this age in the north of France 

 are entirely of freshwater origin, and comprise the larger part of 



