OCR Text |
Show 1900.] FOSSIL MARSUPIAL FROM TASMANIA. 777 embedded in the ' Turritella-zone' of the marine beds at Table Cape "l. Unfortunately it is far from being nearly perfect. Table Cape itself is a promontory near to the little township of Wynyard and looks out northwards across Bass Strait. Close to it are two small bluffs, from one of which a the specimen was obtained. The bluff is about 160 feet high, with a capping of basalt, beneath which lie the Tertiary beds, which in their turn rest on Silurian slates. The upper Tertiary beds, called by Johnston the " Turritella-zone," are about 80 feet where fully exposed and contain in addition to marine forms leaf-impressions. The same author says : " With respect to the occurrence of the plant-remains amongst marine forms, it is most probable that the calcareous sandstones were formed at the mouth of an estuary or river, and that the leaves and other land organisms were washed down and included with the marine forms. This interpretation also throws some light upon the discovery of tbe almost complete skeleton of the species of Halmaturus already derived from the calcareous sandstone." In regard to the underlying Crassatella-bed, he says : " It hardly deserves to be considered as distinct from the Turritella group which rests immediately upon it, were it not for the fact that it appears to have been accumulated under different circumstances." Pritchard3 says in regard to the collection of shells studied by bim that it " came principally from the lower deposits known as the Crassatella-beds, and judging from the fossils I regard the zone as the direct equivalent of the so-called middle beds of the Spring Creek section in Victoria. The coarseness of the material in which a number of the Table Cape fossils is preserved, tbe worn character of many of the species, and the abundance of fragments of shells clearly indicate the littoral character of the deposit, and as an attendant fact of some importance we have certain faunal characteristics indicative of the same feature." In their suggested arrangement of the sequence of the Eocene rocks of Victoria, Messrs. Hall and Pritchard place the Spring Creek beds at the base of tbe series \ The block of sandstone, as it was originally found, had broken off from the face of the bluff and tumbled down to the base, which was surrounded, when the author visited the spot in 1892 in company with Professor Tate, with masses of various sizes strewn about in all directions. Evidently this fall from the upper part of the bluff had smashed the block in such a way as to partially expose the fossil, and subsequent weathering resulted unfortunately in the breaking off of the lower part of the skull ; though it is quite possible that considerable damage had been done to the skull before it was embedded, as the part of the low^er jaw enclosed in the matrix, and so not exposed to recent weathering, has all of 1 Pp. 261, 288 et sap - Figured and described by Mr. Johnston, op. cit. pp. 258 et seq. 3 Proc. R. S. Vict. 1895, p. 77. 4 Proc. R. S. Vict. 1894, p. 180. " The older Tertiaries of Maude with an indication of the sequence of the Eocene Rocks of Victoria." |