Amongst a small collection of fossils lately forwarded to the writer for identification, by Dr. Rankin, of Carluke, from the Carboniferous beds of that neighbourhood, are some remains of Polyzoa, peculiar from the combination of characters presented by them, such as have hitherto been considered characteristic of separate genera. In Fenestella, Miller, as restricted by King, each interstice or stem of the frond is provided on one side only with two or more rows of cell-apertures, separated by a median keel. In Polypora, McCoy, on the contrary, the interstices or dissepiments are not carinated, and the former are always provided with numerous rows of cell-apertures, generally arranged more or less in quincunx, the dissepiments as in Fenestella, being non-celluliferous. In the specimens under consideration a combination of some of the above characters takes place, forming a connecting link between the two genera Fenestella and Polypora. An examination of the accompanying drawings will at once show that the fossils there represented cannot be referred to either of the above, but they, certainly appear to be the type of a new genus, which it is proposed to call Carinella. Only one species is at present known, which might with advantage be termed C. cellulifera.

I was led to make this analysis with the view of determining if possible whether the extreme hardness of the Irish Chalk were due to either a chemical, a mechanical, or a calorific alteration, from the influence of the overlying basalt. If it were owing to chemical change, we should expect to find a large per-centage of silicates and a diminution in the amount of lime; if to the influence of heat, carbonic acid would be driven off, silica would be in excess, and the presence of the insoluble bases, such as the peroxide of iron, oxide of manganese, and alumina, would become more apparent; while if a mechanical cause or pressure were the reason, no change would take place in the relative amount of the constituents. I believe the result seems to show that the induration of the Chalk must be set down chiefly to the last agency,—if to anything apart from the original formation of the rock,—and that the power of alteration exerted over it by the heat of the molten basalt has been small indeed. At the same time a certain addition has been made to it by means of water holding chemical bodies in solution.

As the sands and clays of the Hastings series lie conformably on the Purbeck Beds, it is probable that the same area which formed the embouchure of the Purbeck river performed still the same office during the Hastings Sand age; but the entirely different character of the deposit shows at least that the soil of the country drained by the latter was different from that which supplied the former; and it is evident also that, in the district under consideration, the motion of the water of the Hastings river was much more rapid, from the abundance of sand, coarse quartz, and gravel with pebbles.

I had hoped that ere this some one better acquainted than myself with Irish post-Tertiary Geology would have collected into one memoir the details scattered throughout the various scientific journals, thus enabling English geologists to compare the later deposits of Britain with those of the sister-kingdom. Since no one has done so, I venture to put some notes of my own upon the subject before the readers of the GeologicalMagazine, especially as, in some recent discussions upon the Irish drift, “Palæontological succession” has not received the consideration it may fairly claim.

2. Middle and Lower Cambrian.—Investigations in continental Europe were, meanwhile, preparing the way for a new chapter in the history of the Lower Palæozoic rocks. A series of sedimentary beds in Sweden and Norway had long been known to abound in singular petrifactions, some of which had been examined by Linnæus, who gave to them the name of Entomolithi. They were also studied and described by Wahlenberg and by Brongniart, the latter of whom, from two varieties of the Entomolithus paradoxus, Linn., established in 1822 two genera, Paradoxides and Agnostus.

This name is proposed for a fossil from Oldham resembling Psaronius Zeidleri, Corda; the author records the discovery of specimens of Zygopteris, and his conviction that Cotta's Medullosa elegans is “merely the rachis of a fern, or a plant allied to one.”