BY J. BRAZIER, C.M.Z.S. 235 On some Mesozoic Fossils from Central Australia. By the Rev. J. E. Tenison-Woods, F.G.S., &c. With Two Plates. The fossils described and figured in this paper were obtained by Mr. Gilliatt, one of the surveyors in the Mining Department. They were found in sinking a well on Mount Stewart Run, which is situated on the Grey Ranges. The fossiliferous bed was struck at a depth of 90 feet. The remains comprise many specimens of Avicula, some Grypheoe, a Trigonia. Belemnite, Pecten, Ostrea, Pinna, Cyprina, Mytilus, and many broken fragments. The only species which can be determined, are of Avicula, Pecten, Trigonia i.nd Belemnites, the rest being too imperfect. The sand is of a greyish green color, with numerous blackish grains. In places it is finely levigated, so as to preserve impressions of the faintest markings on the shells. Some portions are a coarse grey green sand, easily powdered. Under the microscope, this sand is seen to be composed of angular fragments of crystals, with small portions of shelly matter. There were very few rounded grains ind none polished. When treated with hydrochloric acid, there vas only a slight effervescence, confined I suppose to the fragments of shelly matter. I could not dectect any Foraminifera. Some of ■he fragments of crystals were dark black or green, some opaque vhite, and some transparent. There were also a few brown opaque grains. The transparent grains seen in polarized light, all showed )ands of color and some twin crystals and triclinic felspar. The "arge green crystals were dark and opaque ; some of the smaller lark grains had almost a metallic lustre. From the absence of my glassy particles, as well as there being so little marks of ferric )xides, we may conclude that this sand was derived from the weathering of some of the ancient granite rocks, and not from volcanic or trap rocks. There is a general external resemblance in the rock to the greensands of Britain and France, but the resemblance is merely external. There is no trace of the glanconitic
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