NEW OOLITIC MAMMALIA. 647 



again -without retaining on its surface any monuments of the kind 

 usually demanded as indispensable to warrant us in speculating on 

 marine denudation as a great modifying cause in the physical geography 

 of the globe. 



NEW FOSSIL MAMMALIA FROM THE PURBECK OR UPPER OOLITIC 

 STRATA IN DORSETSHIRE. 



Discovery in Dorsetshire of seven or eight new genera of Mammalia in the Pur- 

 heck or Upper Oolite strata — First example of a skull of a Mammifer from 

 Secondary Eocks — Insectivorous Marsupials and Placentals and herhivorous 

 Marsupials — Figures and descriptions — Light thrown on the Microlestes or 

 oldest triassic Mammifer — General bearing of the new facts. 



It will be seen by the text (p. 45*7) that when the 5th edition of this 

 work was published two years ago, six species only of mammalia were 

 known in the whole world from rocks older than the Tertiary. The 

 researches of 36 years had been required to bring these six species to 

 light, from 1818, when first a lower jaw from the Stonesfield Oolite, 

 found 10 years before, was pronounced by Cuvier to be mammalian, 

 to the year 1854, when the Spalacotherium of Purbeck was described 

 by Owen. 



Figures are given at p. 341 of two small molar teeth of the most an- 

 cient of these six quadrupeds, the Microlestes of Plieninger, found in a 

 bone-bed near Stuttgart usually referred to the Upper Trias, and in 

 which Triassic species of fish and reptiles abound. Figures are also 

 given of the fossil lower jaws with teeth of three diminutive mammalia 

 obtained from the inferior oolite of Stonesfield (pp. 311-12 of the text, and 

 368, 4th ed.), and supposed to belong to insectivorous creatures, one of 

 them at least to a marsupial quadruped. The remains of a fourth 

 British mammal, also consisting of a lower jaw from the same locality, 

 found by the Rev. J. B. P. Dennis, and made known in September, 

 1854, is alluded to in a note at p. 457. Although small, it was con- 

 siderably larger than the three 6pecies previously discovered, being 

 probably about the size of a rabbit. Professor Owen imagines it to have 

 been of omnivorous habits, and one of the ungulate or hoofed quad- 

 rupeds, allied to certain extinct genera of the tertiary period, called 

 Hyracotherium, Microtherium and Hyopotamus. 



The discovery in Purbeck, Dorsetshire, in 1854, of the Spalacotherium, 

 a small insectivore allied to the Cape mole, is mentioned at p. 295 and 

 457, as the first example of a mammifer from those freshwater strata. 

 In December last (1856) Mr. Samuel H. Beckles, F. G. S., conversed 

 with me in London on the desirability of quarrying the Middle Purbeck 

 in Durlestone Bay, near Swanage, for the express purpose of exploring 

 the fossil contents of the bed in which Mr. W. R. Brodie had procured 



