490 



THE WONDERS OF GEOLOGY. Lect. V. 



The observations of Dr. Buckland on this problem 

 entirely accord with the result of my own investigations. 



" The general absence of pebbles shows that the lands were distant 

 whence the fine particles of sand and clay were transported. It is not 

 probable that the materials of the Wealden formation have been 

 derived in any great degree from the detritus of the oolitic series, 

 because in such case we should find among them an admixture of 

 pebbles of oolite, none of which have yet been noticed, — we should be 

 inclined rather to look for the lands whence the strata have been sup- 

 plied, either in Devonshire or Cornwall, on the west ; or in the nearest 

 primary and transition mountains of the Continent, viz. in Normandy 

 and Brittany, on the south-west ; or in the forest of Ardennes, on the 

 south-east."* 



Of the seaward extension of the delta of the Iguanodon 

 river, no certain indications have yet been obtained : but it 

 is evident that there must have been intercalations of the de- 

 tritus and organic remains of the land and fresh-water, with 

 those of the sea into which the mighty stream discharged 

 its waters ; and there can be no doubt that sooner or later 

 these fluvio-marine wealden strata will be discovered. 



5. Medial Secondary Formations. — In accordance 

 with the chronological arrangement (p. 200), I proceed 

 to the consideration of the antecedent or medial group 

 of the secondary formations, namely the Oolite, Lias, and 

 Trias, As a whole, the series consists of alternations 

 of clays, marls, limestones, sands, and sandstones, abounding 

 in marine exuviae, and which have evidently been deposited 

 in the basin of a sea or seas. With these strata are 

 intercalated in some localities beds of fluvio-marine de- 

 tritus, in which vestiges of land animals and plants are 

 imbedded. 



The fossil remains of the inhabitants of the sea comprise 

 a prodigious number of zoophytes, crinoidea, mollusca, 



Geology of the Isle of Wight, p. 193. Dr. Fitton mentions having 

 found a rolled ammonite in the Wealden. 

 * Geol. Trans, vol. iii. new scries. 



