Geology of the Neighbourhood of Weymouth, Sgc. 1 1 



served by Mr. De la Beche* and M. de Caumont in Normandyf, where it 

 overlaps successively the formations of Kimmeridge clay, coral rag, and Ox- 

 ford clay. This circumstance derives an additional importance, at the present 

 time, from the recent paper of M. Elie de Beaumont];, in which he observes 

 that a connexion exists between the elevation of mountains and succeeding 

 deposits of extensive overlapping strata, e. g-. the greensand and chalk in 

 the Jura mountains, filling the longitudinal valleys produced by the elevation 

 of the oolites. On the coast of Dorsetshire no elevation of the strata appears 

 to have taken place between the deposition of the lias and the plastic clay. 



Hastings Sand, and Purbeck Beds. 



Although the Wealden or Hastings sands do not enter the area of our 

 actual observation, they approach very near to its eastern extremity, becoming 

 gradually thinner in their progress westward through the Isle of Purbeck, 

 until they terminate a little west of Lulworth : this has been already pointed 

 out by Dr. Fitton and Mr. Webster§. 



The identity of this Hastings sand with that of Swanwich Bay, at the east 

 extremity of Purbeck, has recently been further confirmed by the Rev. T. O. 

 Bartlett's discovery of the remains of the Iguanodon and other reptiles in the 

 iron sandstone at Swanwich. Bones of this animal have also been recog- 

 nised by Prof. Buckland and by Mr. Vine in the same sandstone at Sandown 

 Fort, and other places on the south coast of the Isle of Wight. 



The Purbeck beds enter our district on the north-west of White Nore, but 

 are seen only in two small insulated patches near the villages of Osmington 

 and Upway. The details of the beds composing the Purbeck series are so 

 fully given by Mr. Webster ||, that it is here superfluous for us to say anything 

 respecting them, further than that several of their most remarkable varieties 

 are recognised and wrought even to their final termination on the west of 

 Upway. We trace also throughout this district the remarkable beds of fi- 

 brous carbonate of lime that pervade the clay which alternates with the beds 

 of limestone throughout the Isle of Purbeck. The fibres of this limestone, 

 like those of satin spar, are at right angles to the planes of the beds which 

 they compose, and which vary from two to six inches in thickness. From 

 the resemblance of its small and parallel fibres to the fibres of animal muscle, 

 this limestone is known among the workmen by the name of " Beef" : it 



* Geol. Trans. Second Series, vol. i. Part I. PI. X. •{■ Essai sur le Top. Geog. PI. VI. 



X Ann. des Sciences Nat. vol. xvii. Sept. 1829. § Annals of Philosophy, 1824^ New 



Series, vol. viii. p. 382: also Sir H. Englefield's History of the Isle of Wight, p. 194. 

 II Geological Transactions, Second Series, vol. ii. p. 36. 



c 2 



