age, a fact which, is now generally recognized, whilst by others they were referred to the Jurassic or the Triassic period*), the first positive evidence that was made known of any fossils of Mesozoic age was through the researches of E. T. Gregory, Esq., who, in a paper on " The Geology of a part of Western Australia," communicated to the Society by Sir Roderick Murchison, and published in the Quarterly Journal, vol. xvii. 1861, p. 475, notices the presence of what he considers Cretaceous rocks in that district. The group, he remarks, partly consists of chalk-like rocks and ferruginous sandstone, containing Ammonites, Trigonioe, and Pectens. " The bed of the Greenough river," he states, "is the best spot for procuring specimens, although a few are to be found in the chalk-hills near Gingin (spines of Echinoderms &c.)." The specimens exhibited at the reading of Mr. Gregory's paper are now in the possession of the Geological Society, and consist of a single cast of Trigonia Moorei (Lycett), and a very much worn Pecten, of uncertain species, both evidently of Oolitic age. They were accompanied by a Ventriculites in flint, and a portion of a chalk Ammonite, and also by a considerable number of specimens of the age of the Carboniferous Limestone.
Meagre as was the evidence thus afforded, it was still sufficient to show, for the first time, the presence of two groups of Mesozoic rocks, the Oolitic and the Cretaceous, in Western Australia.
It is not improbable, from the remarks of Mr. Gregory, that the latter are in situ ; but hitherto we have no record of the actual presence of stratified Oolitic beds. It is probable that the two specimens may have been obtained from the bed of the Greenough River, as they are evidently drifted fossils, a character which will be found to be general with other remains to be hereafter noticed.
The next, and, up to this time, the most important notice connected with the Mesozoic Australian fauna was due to the Rev. W. B. Clarke, and related to the discovery, by Mr. Gordon, in the neighbourhood of Wollumbilla, of a large number of organic remains which will be more fully noticed hereafter. These were to have been in England in time for the last Exhibition, but had not then arrived.
In that Exhibition, however, there might have been noticed a set of fossils, forwarded by Mr. Shenton from the Greenough Flats and other districts of Western Australia, which were not only the most numerous but the best-preserved Australian secondary fossils that had yet been publicly exhibited in this country. These consisted of Ammonites macrocephalus, Belemnites canaliculatus, Trigonia Moorei, and species of Ostrea, Lima, Astarte, Cuculloea, Myacites, Rhynchonella, &c, all evidently of Oolitic types, and identical with species that will be noticed below as occurring in Mr. Sanford's collection. I could not open the cases to give them a very critical examination ; but there appeared to be about fifteen species in the series, together with fossil wood, apparently from the same formation. In addition to the above, there was a siliceous cast of a Micraster from the chalk, and some vegetable impressions in a cherty sandstone, the age of which I could not recognize. I had hoped to secure these fossils,
- See W. B. Clarke, Quart. Journ. Geol. Soc. vol. xxiii. p. 11.
