Red, pass up into the Ursa stage of the Lower Carboniferous, represented, however, probably by other species than in the Old Red of Scotland. This happens also among the plants ; and among the lower animals, not only many genera, but even numerous species pass up from the Devonian to the Mountain Limestone.
It is much to be regretted that the plants of the Marwood beds, and the Lower Carboniferous flora of England and Scotland generally, have been so imperfectly studied. They would certainly furnish very valuable materials for the decision of the much-vexed question where the limits are to be drawn between the Devonian and the Carboniferous in Devonshire.
On the Continent the flora of the Greywacke of the Vosges and of the southern Black Forest belongs to the Ursa stage. Of the twelve Vosges species which Prof. Schimper has described, nine occur in Bear Island, and four have been recognized in Ireland. Calamites radiatus, as in Bear Island and in Ireland, is very common, and forms, together with the Lepidodendra, Stigmarioe, and Knorrioe, the chief mass of the plants.
At Moresnet, in the neighbourhood of Aix, immediately under the Carboniferous Limestone, occurs a shale which rests upon the Eifel Limestone. This shale yielded Paloeopteris Roemeriana, and Spirifer disjunctus, Sow., and was entitled by Herr von Dechen the Verneuilii-shale, and placed at the uppermost limit of the Devonian. As, however, this Spirifer is also present in the Carboniferous shales of Ireland*, and therefore passes up from the Devonian into the Lower Carboniferous ; and as we meet with the fern among the plants of Bear Island, we may probably class these Verneuilii-shales of Aix with the Ursa stage, and draw the dividing line with all the more reason below them, since they lie in unconformable stratification upon the Eifel Limestone.
Among the American fossil floras, that of St. John's, New Brunswick, belongs, according to my view, to the Ursa stage, and not to the Devonian, in which Dawson has placed it. Dawson's list (' Acadian Geology,' p. 534) contains forty-eight species ; of these, thirty-seven have not been found elsewhere, nine are known in the Carboniferous, and three in the Devonian. The greater number, therefore, of those which are common to other localities belong to the Carboniferous ; and it is remarkable that two of the Devonian species are only represented by a few leaf-fragments, and their determination may be still doubtful ; while among the Lower Carboniferous species the Calamites are very abundant, and Calamites radiatus in some places fills whole strata, and is therefore quite as abundant as in Ireland, Germany, the Vosges, and in Bear Island. To this it may be added that, among the thirty-seven species of St. John's which as yet have not been found elsewhere, twelve agree so nearly with Carboniferous species as to be only di-
- [This Spirifer disjunctus was stated, in the Memoir of Salter and Baily
relied upon by Prof. Heer, to have occurred in the Carboniferous strata of that country ; but this has since been ascertained by Mr. Etheridge to have been a mistake.]
