PURBECK FORMATIONS. 21 



not later than the Lower Oolite ; or, like the Lettenkohle of Germany, of Triassic age. 

 The Mammalian remains are associated in the CaroHna- Virginia Coal-fields with those of 

 thecodont Reptiles.^ 



c. Mammals from Purbeck Beds. 



The strata of the Isle of Purbeck, on the Dorset coast, intervene between the ' Upper 

 (Portland) Oolites' and the 'Wealden' (see Table I, p. 4). They have been successfully studied 

 and accurately described by Mr. Webster,^ Dr. Buckland,^ and Dr. Pitton,* whose conclusions 

 have been verified with additional details, both palaeontological and geological, by sub- 

 sequent observers, especially by the able and accomplished officers of the Geological Survey 

 of Great Britain, to one of whom, Robert Etheridge, Esq., P.G.S., Palseontologist to the 

 Survey, I am indebted for the subjoined diagram of the deposits at Durdlestone Bay (Fig. 4), 

 including those from which the Mammalian Fossils of the 'Purbeck' described in the present 

 Monograph have been obtained. 



§ VI. Genus — Spalacotherium, Owen, 1854.^ 



Species I — Spalacotherium tricuspidens, Ow. PI. I, figs. 32, 32 a, 32 b, 32 c, 33, 



33 A, 33 B, 33 c. 



Quart. Journ. Geol. Soc, vol. x, p. 426, 1854. 



After Emmons' discovery the next evidence of a Mesozoic Mammal was obtained 

 from a deposit of later date, one of those which are known as the ' Purbeck Series,' 

 richly developed in the peninsula of that name, at Durdlestone Bay, near Swanage, 

 Dorsetshire. 



In the year 1854 a series of small fossils from that locality were sent to me for deter- 

 mination by Messrs.WiLCOx and Brodie, of Swanage. The majority of the specimens were 

 Saurian, and aflforded characters of the lacertian genera Nuihetes, Maeellodics, Saurilhs, &c. f 

 but some appearances of the teeth in small jaws among Mr. Brodie's specimens, suggesting 

 evidence of a higher grade of life, attracted and excited close and continued scrutiny. 



At first sight the specimens appeared, as their discoverer had supposed, to differ only 

 in species from the similarly sized jaws of the Saurians with which they were associated, 

 and it was only after a careful removal of the matrix concealing their most characteristic 



' ' American Geology,' part vi, 1857, p. 93. A copy of Emmons' figure, and of the reference thereto, in 

 my ' Palaeontology,' 8vo, 18C0, p. 302, is given in Dana's excellent ' Manual of Geology,' Svo, 1864, pp. 426, 

 429, and fig. 650. 



2 ' Geol. Trans.,' 2nd series, vol. ii, p. 36. 3 ib., vol. iv, p. 11. ^ lb., ib., p. 208. 



^ ' Quarterly Journal of the Geological Society of London,' vol. x, p. 426. 



6 lb., p. 420. 



