The specimens placed in my hands by Mr. N. Plant from Rio Grande do Sul consist of a few specimens of coal and a considerable number of a highly ferruginous shale. The coal contains no recognizable fossils, but they abound in the shale. The substance of the plants is converted into a brittle coal, that possesses no structure, and exhibits the form only of the organism, but the superficial structure and the venation is often so beautifully preserved on the surface of the shale, when the coal is removed, that the nature of the fossils is very clearly exhibited. I have, thus, been able to determine with precision three species, and to recognise more vaguely a number of other forms, which, however, it would be injudicious, until additional material is obtained, to name or describe from the specimens in my possession. All these forms, as far as they can be determined, and certainly the three well-preserved species, belong to Palseozoio genera, species of which occur in the Coal-measures of Britain. We are thus enabled with certainty to refer the Coal-fields of the province of Rio Grande do Sul to the Carboniferous period, although the coal itself has more the aspect of being the product of a Secondary formation.