On some Fossil Foraminifera from Chellaston near Derby

Abstract

Having thus pointed out that, judging from these specimens obtained at Chellaston, the minute Nodosarinœ and other Foraminifera of the Triassic period have continued to exist through the intermediate ages to the present day without losing any of their essentially specific features, we will observe that the Nodosariœ are present in rocks of still greater age than the Trias—namely, the Permian and Carboniferous, and probably even the Lower Silurian, Nodosariœ and Dentalinœ abound in some of the Permian limestones of Durham and the Wetterau in company with Textulariœ . Nodosaria occurs also in the Carboniferous Limestone of Ireland, according to M’Coy; and the green sand of the Lower Silurian series near St. Petersburg has yielded to Ehrenberg casts of chambers something like those of Dentalina , together with unmistakeable casts of Textularian and Rotalian shells. We may remark, too, that the Fusulina of the Russian, North American, and Arctic Mountain-limestone carries back the pedigree of the Nonionina -group to the palæozoic periods, and that it is accompanied with other Foraminifera of known types, amongst which the Nummulina is not absent. This last-named type has rare representatives in the Lias and the Oolite; it acquired great potency in the Tertiary seas, and is not extinct now. Altogether we have here some remarkable instances of the persistency of life-types among the lower animals. Though the specific relations of the Palæozoic Foraminifera require further elucidation, we feel certain that the 6 genera represented in this Upper Triassic clay of Chellaston by about 30 varieties stand really