J. C . Mansel-Pleydell — Geology of Dorset. 409 



animal matter. Like the Lias of the -vvestern side of the county, it 

 yields a rich supply of Saurian and Cephalopod remains, much im- 

 pregnated with iron pyrites (a compound of iron and sulphur in 

 proportion of 45-77 to 54-23), several of which have been figured 

 and described by Prof. Owen, F.E.S., and Mr. J. W. Hulke, F.R.S. 

 Among the most important is the humerus of a gigantic terrestrial 

 animal vjang with the Iguanodon and Megatherium in its magni- 

 tude, and of strong crocodilian affinities. Traces of such a gigantic 

 Saurian have been met with previously in an ungual phalange from 

 the Kimmeridge Clay at Ely, and a fibula from Holworth, both of 

 which are in the British Museum. In the Earl of Eldon's collection 

 at Encombe there is a similar humerus. 



During the year 1871 an entire skeleton of Iclithyosaurus en- 

 thekiodon (Hulke) has been added to our palceontological list, as well 

 as the anterior part of the upper jaw of a Teleosaur, which is the 

 first indication of this genus discovered at Kimmeridge. Before dis- 

 missing this part of the subject, it may be stated that the occurrence 

 of two species of Plesiosaurus from Kimmeridge have been confirmed 

 by Mr. Hulke, P. bracMstospondi/lus and P. Manselii. The com- 

 parison of the limbs of the latter with those of the typical Liassic 

 Plesiosauri brings out so many and such important dilferences that 

 this and P. megadeirus from Haddenham and Ely may well rank as 

 the representatives of a very distinct sub-genus. 



In addition to the evidence of the proximity of land during the 

 formation of the Kimmeridge beds by the remains of the terresti-ial 

 Dinosaur, a fossil plant, Pinites depressus, from the Kimmeridge Clay 

 near Weymouth, has been confirmed and figured by Mr. Carruthers, 

 F.R.S. 



Portland Sand. — The Portland Sands are about 100 feet thick 

 in Purbeck, and from 60 to 80 feet in Portland ; they consist of 

 light-grey, soft, siliceous matter, including minute green particles, 

 and, like the Liassic sands of the western side of the county, repose 

 upon inferior clay -beds ; it includes indurated nodules in horizontal 

 layers, which frequently contain Trigonice and Fanopece. It meets 

 the coast-line between Winspit and St. Alban's Head, and crops out 

 in the longitudinal valley from Pier Bottom to Encombe, and from 

 the base of the Oolitic range which commences at Encombe and 

 terminates at Gad Cliif ; the sands re-appear beneath the Portland 

 Stone near Stair Cove, and again at Eingstead; the great Eidgeway 

 fault throws them northward, and near Poxwell they take a westerly 

 direction, half encircling the valley of Sutton Poiutz on its eastern 

 side, and forming the base of Chalbury Hill ; after a slight inter- 

 ruption at Bincombe they continue to the village of Portisham, 

 leaving Upwey and Friar Waddon on the north. 



Portland Stone. — Here is the first appearance in the West of 

 England of the Portland stone, which attains an elevation of nearly 

 500 feet at Preston and Bincombe, and constitutes a large portion of 

 the Isle of Portland. It rises at an angle of nearly 90 degrees on 

 its northern side towards Weymouth, with its base upon the Kimmer- 

 idge Clay. It skirts the sea-level at Lulworth, and forms a magnificent 



