234 Dr. ManteWs Isle of Wight. 



The Iguanodon, Megalosaurus arid Hylaeosaurus appear to have 

 formed a peculiar group of land lizards — the first herbivorous — 

 the second carnivorous, and the last not yet determined. 



The 12th and last chapter of Dr. Man tell 's work contains a 

 detailed- notice of the geology and topography of the neighbor- 

 ing coast, which abounds with interesting and instructive facts, 

 among which the petrified forest of the oolite of the peninsula of 

 Portland is one of the most remarkable. 



The retrospect which closes the volume is so fine a specimen 

 of geological induction that we insert it entire. 



" In attempting to interpret the natural records of the earth's 

 physical history, the geologist is often in the condition of the 

 antiquary who endeavors to decipher an ancient manuscript, in 

 which the original characters are obscure and partially obliterated 

 by later superscriptions. It is, indeed, frequently difficult, and 

 sometimes impossible, to determine the synchronism of those 

 geological changes, of which the only indications are insulated 

 and but obscurely related phenomena. Bearing in mind the 

 caution of a distinguished philosopher, ' that the language of 

 theory can never fall from our lips with any grace or fitness, un- 

 less it appear as the simple enunciation of those general facts 

 with which by observation alone we have become acquainted,' 

 we will take a retrospective view of what has been advanced, 

 and endeavor to deduce therefrom some general results as to the 

 nature of those physical mutations, of which we have obtained 

 such unequivocal proofs. Fortunately, the evidence of the Vfr 

 portant changes which the organic and inorganic kingdoms of 



nature have undergone in this part of the globe, during the vast 



periods embraced by our researches, is so conclusive, that the 

 attentive reader will perceive the following inferences, startling 

 as they may appear, naturally result from the facts that have 

 been submitted to his observation. 



"i The Oolitic Epoch. — The most ancient deposits com- 

 prehended in our Excursions, are the upper beds of an oceanic 

 formation of great extent— the Oolite — which is characterized 

 by numerous peculiar species and genera of marine reptiles, 

 fishes, moilusks, radiaria, corals, zoophytes, &c. With these 

 strata are intercalated in some places, deposits of variable extent 

 and thickness, containing carbonized vegetable remains, and the 

 stems and foliage of palms, arborescent and herbaceous {&&% 

 cycadeous plants, and conifera ; with bones and teeth of terres- 

 trial reptiles, and of marsupial and insectivorous mammal^ 

 associated with vestiges of insects. These beds are evidently 

 attributable to the action of rivers and streams, by which the 

 spoils of the land were transported into the abyss of the ocean. 

 But our present survey only refers to the period when a portion 

 of the bed of the Oolitic sea was elevated above the waters, 



