and on the Fauna and Flora of the Wealden Formation. 91 



well known by the names of Sussex, Petworth, and Purbeck Marble ; 

 the latter was in great request in the mediaeval ages, and is the ma- 

 terial of which numerous tombs and monuments, and cluster columns 

 in our ancient Cathedrals are constructed. Two common inhabitants 

 of our pools and streams, the Planorbis and Limneus, also occur. 

 Several species of Unio, some of which rival in magnitude the pearl- 

 mussels of the Ohio and Mississippi, likewise abound in the Wealden 

 deposits. Fresh-water Entomostraceans, Cyprides, of several species, 

 swarm in many of the clays and ironstone beds of Sussex and the 

 Isle of Wight. 



The Flora of the country of the Iguanodon appears to have been 

 as rich and diversified as the Fauna. Forests of Coniferce, refer- 

 able or closely allied to Abies Finus, Araucaria, Cupressus, and 

 Juniperus, clothed its hills and plains : with these were associated 

 arborescent and herbaceous Ferns, comprising upwards of thirty 

 species ; together with many Cycadeacece, and trees allied to the 

 Dracaena, Yucca, &c. Equisetaceous and Lycopodiaceous plants 

 also abounded ; and even the common inhabitants of our streams, 

 the Charce, flourished in the rivulets of that marvellous region. 



As examples of the vegetation of the Wealden period, Dr Mantell 

 described the petrified forest of Coniferse and Cycadese in the Isle of 

 Portland : the accumulation of fossil firs and pines exposed on the 

 southern shore of the Isle of Wight ; and the coal-field of Hanover, 

 which entirely consists of the carbonized foliage, trunks, and branches, 

 of coniferous trees, drifted from the country of the Iguanodon. 



The facts thus rapidly noticed prove that during the deposition of 

 the Wealden, Oolitic, and Cretaceous strata, there existed an exten- 

 sive island or continent, diversified by hills and valleys, and tra- 

 versed by streams and rivers teeming with fishes, crustaceans, and 

 mollusca, closely allied to types which at present inhabit the fresh 

 water of temperate regions ; and that with these were associated 

 fluviatile turtles, and crocodilian reptiles, whose living analogues are 

 restricted to tropical climes. Colossal herbivorous and carnivorous 

 saurians, differing essentially in structure from all known existing 

 forms, were the principal inhabitants of the dry land ; and these, 

 together with flying lizards, and possibly a few birds, and very small 

 mammalia, constituted the vertebrate fauna of the country, or coun- 

 tries, which supplied the materials of the Wealden strata, and of the 

 fluvio-marine deposits which are intercalated with the purely oceanic 

 beds of the oolite and chalk. 



Thus it appears, according to the present state of our knowledge, 

 that the classes Mammalia and Aves, which constitute the essential 

 features of the terrestrial zoology of most countries, were represent- 

 ed through a period of incalculable duration solely by two genera of 

 very diminutive mammals, and a few birds ; while the air, the land, 

 and the waters, swarmed with peculiar reptilian forms, fitted for 

 aerial, terrestrial, and aquatic existence. 



