Part of my collection of fossil fishes were sent to the care of my much lamented friend the late J. E. Bowman, Esq., of Manchester, shortly after I found them; these were exhibited by him at the Meeting of the British Association at Glasgow, where they were seen by M. Agassiz, and although no specimens of the rocks accompanied them, he immediately, from their zoological characters alone, pronounced them to belong to the chalk series. It is well known that this learned naturalist divides all fishes into four great classes, from the nature of their scales; two of these, the _Ctenoid_ and _Cycloid_, never make their appearance in any of the rocks beneath the chalk, and it was from his knowledge of this fact that he decided my specimens to be from that formation, as they consisted chiefly of individuals of the _Ctenoid_ and _Cycloid_ groups. The fishes are in a most perfect state of preservation, and, as I have already stated, are included in an impure fawn-coloured limestone; the blocks, however, in which they are preserved, are only nodules contained in the yellowish coloured sandstone. They have in general somewhat the form of the imbedded fish, and the carbonaceous matter was apparently aggregated round them by chemical attraction from the sandstone while in a soft state; these nodules being harder than the sandstone, have, by its gradual decay, accumulated at various places along the acclivity of the range, and I possess specimens both from the east and west side of it.[6] On the evening of the 23rd of December I had an invitation from Lieut. Col. João José de Gouvea, a gentleman to whom I brought letters, to accompany him and the Visitador to a place called Maçapé five leagues to the east of the Villa da Barra do Jardim, whither they were going to pass Christmas Day. This I gladly accepted, having been already informed that a large deposit of fossil fishes existed there. We started at eight o’clock on the morning of the 24th, and as the Visitador was not to return, he was accompanied for nearly a league from the Villa, by about half a dozen of the most respectable persons in the neighbourhood, Senhor Gouvea, his lady, and Senhor Machado, and I went on to Maçapé. At about half a league from the Villa we entered a narrow ravine, wooded on each side with large trees, the branches of which were bearded with the long _Tillandsia usneoides_, and another large species of the same genus, but I did not observe a single Orchideous plant. This ravine is nearly half a league in length, and about the middle of it arises a spring yielding an abundant supply of cool and limpid water, which lower down is applied for the purpose of irrigation. As the ravine rises gradually, the ascent of the Serra here is less steep than by the one we passed on the road from Crato. Immediately on entering the Taboleira the vegetation changes, none of the trees seen there being found below, but I did not perceive