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From tlie Hartwell brickyard, situated in the valley, consisting 

 of a black sandy Kimmeridge clay, M. S/emann collected 

 Ammonites biplex, Belemnites Souichii, Pleuromya Tellina, Thracia 

 depressa, Cardium Morinicum, Penia Boucliardii, Mytilus Bolon- 

 iensis, Pecten Morini, Lima Boloniensis, Ostrea expansa, and 

 many other shells in a fine state of preservation, of which only 

 one — Astarte Hartwelliensis, Sow. — appears to have been figured. 

 Ammonites biplex is very abundant, and sometimes it is most 

 perfectly preserved in the clay, or enclosed in geodes. These 

 fossils are found at Hartwell in the same proportion and 

 abundance as at Boulogne, and their association proves 

 undeniably the existence of the middle Portlandien of the 

 Boulonais in England. The clays, with Cardium Morinicum, 

 are overlain by sandy and argillaceous beds, some of which are 

 fossiliferous, containing Pleuromya, JJnicardium, and Thracia 

 angulare. This bed likewise occurs at Shotover, where it 

 contains Ammonites. The upper portion of the sand is 

 concealed by vegetation, and above this is a quarry of Portland 

 stone, with Ammonites giganteus, extensively worked at Hartwell; 

 both the flat and inflated varieties of this shell occur; the 

 flattened forms resembling the Ammonites of the Middle 

 Portlandien of the Boulonais, with Natica elegans, Natica 

 Ceres, Cardium, Pellati, Cardiu/m dissim,ile, Trigonia incurva, 

 Trigonia Pellati, Lim^a rustica, Pecten lamellosus, Ostrea expansa, 

 and Serpula coacervata. Numerous traces of this annelide are 

 seen on the Ammonites. These Portland marine beds are 

 overlain by the estuarine Purbeck strata, consisting of shales, 

 clays, and marly limestones, full of freshwater organisms, as 

 Cyrence, Cyprides, and fishes, with the remains of insects, and 

 lacustrine plants. The Wealden beds are hkewise represented 

 in this instructive section, as we have Cyrena, TJnio, and 

 Paludina, with the Wealden plant Endogenites erosa. The hill 

 is capped by Lower Greensand, or Neocomian strata, containing 

 Exogyra sinuata, Pecten ohliquus, Ostrea macroptera, &c. Prom 

 this section it is inferred, 1st, — that the Lower Portlandien of 

 the Boulonais, with Perna rugosa and Pterocera Oceani, is not 

 represented here, 2nd, — that the dark sandy clays of Hartwell 



