262 JURASSIC. 



as Hyhodus, allied to the Catracion and Chinuvra. The term 

 Ichthyolite is applied to any portion of a fossil Fish. 



The Reptiles include species of /c/;//y^c.faz/r//j' and Plesiosaurus ; of 

 the former, specimens twenty-four feet in length have been ob- 

 tained ; and of the latter, with its long neck, specimens have 

 measured from eighteen to twenty feet. The Ichthyosaurus was 

 first found in 1811 at Lyme Regis, by Miss Mary Anning, and the 

 same lady subsequently discovered the Plesiosaurus, and in 1828 the 

 Ptcrodaciylus. Lyme Regis has furnished many famous specimens, 

 some of which, obtained many years ago by Mr. Thomas Hawkins, 

 formed the subject of his great books on " Sea-Dragons."^ 



Remains of Plants, Equisetites, Naiadites, and Otopteris, have been 

 recorded from the Lower Lias. In the upper clayey beds of the 

 Lower Lias the fossils are often pyritic, being coated with or 

 replaced by Iron-pyrites. 



Among the many places of interest in England, few have, 

 perhaps, attracted more geological visitors than Lyme Regis. The 

 numerous remains of Fishes and giant Reptiles, not to mention the 

 many and varied forms of invertebrate life, have enticed many an 

 eager collector. It is true that the Lias has yielded an abundance 

 of organic remains ; and yet some who visit the cliffs of Lyme 

 Regis in search of specimens return disappointed. The fact is, the 

 fossils occur at particular horizons, and it is only by much time and 

 labour that good specimens can be obtained. It is not that Lym.e 

 Regis was a specially favoured locality for the entombing of organic 

 remains — the large exposures of Lias, and the number of collectors, 

 have made it famous. 



The thickness of the Lower Lias of Dorset may be estimated at 

 about 450 feet. The coast-line between Axmouth and Bridport 

 Harbour exhibits a complete section from the Rhcetic Beds to the 

 sands below the Inferior Oolite. The beds are disturbed here and 

 there and sometimes repeated by faults, moreover there are many 

 landslips, hence precise measurements are difficult ; but with care 

 the entire sequence of the beds may be traced. 



One of the earliest accounts of the Lias of Dorsetshire was by De la Beche,^ 

 but the stratigraphical and palajontological details of the Lower Lias were first 

 noted by Dr. Wright,^ and those of the Middle and Upper Lias by Mr. E. 

 C. H. Day.i 



The various divisions are shown in the section (Fig. 40, p. 252). Starting from 

 the west of Lyme Regis, we find at Pinney (Pinhay) Bay, a section of White Lias 

 (Rhajtic Beds), overlaid by the Lower Lias. In the zone of Avimonites planorbis, 

 which rests on the White Lias there and at Uplyme, that fossil is not common, 

 although it has been obtained : the cliff-sections however are not very accessible. 

 To the east of Pinney Bay, we come gradually to the zone of A. Biicklandi, the 

 intermediate zone of A. augidatus not being distinctly represented, although the 

 species does occur. The limestones (altogether about 100 feet in thickness) which 

 form the West Cliff, to the west of Lyme Cobb, belong mainly to the zone of 



^ Memoirs of Ichthyosauri, etc., 1834; The Book of the great Sea-Dragons, 

 etc., 1840. The extinct marine Saurians are sometimes termed Enaliosauria. 

 - T. G. S. (2), ii. 21, and Report on Geol. Cornwall, etc. 

 2 Q. J. xvi. 374 ; and Lias Ammonites (Palceontogr. Soc), p. 38. 

 * Q. J. xix. 278. 



