The two Star-fishes represented in our Plate form part of a group of six specimens found associated together in the same mass of Chalk at Bromley, Kent, by the late well-known collector, Jeremiah Simmons, of whose persevering and successful labours in obtaining fossils from the Chalk formation abundant evidence may be seen in the beautiful series of Echinodermata in the cases of the British Museum of Natural History, some of which formed a part of the Dixon and Bowerbank Collections. He also collected for the Marquis of Northampton, and a fine Collection of Chalk Fossils made by Simmons is now preserved in the Woodwardian Museum at Cambridge.

“Having often been puzzled to comprehend the manner in which,insome instances, large numbers of marine animals, such as Cuttlefishes, Crabs, Lobsters, and even Fish and Reptiles, have in past ages suddenly perished in their own element and been entombed, probably on or near the very spots where they had been hatched out, and which they had frequented all their lives, it has occurred to me that any suggestion as to causes now in operation which might have produced then, as now, the same result, will not be unwelcome to the geological student. in the ‘Principles of Geology’ (7th edit. 1847) Sir C. Lyell mentions (p. 743), among other causes, the shifting of currents which might result in the carrying away of banks of sand and mud, habitats of vast colonies of cockles and other molluscs; and the effect of a stormintearing up and casting ashore from their more solid bed great heaps of the edible oyster in the estuary of the Firth of Forthin1831, and numbers of living whelks.

Length of a typical spine 1⅞ inches; greatest diameter, inch. The spine is thickest about half an inch from its proximal extremity, towards which it slightly contracts, while distally it tapers to a fine point; its contour is at first straight, then becoming gently curved backwards towards the apex. Transverse section at first round, but near the middle of the spine a flattened atea commences, running along the posterior margin, and as this is followed onwards, a delicate median ridge appears, and is continued to the apex. Along the boundary, on each side, of this posterior area, a right and left row of denticles is seen extending from the apex to three-quarters of an inch from the base: they thus occupy a greater extent of the length of the spine than the area in question. These denticles are about 38 on each side, opposite, closely set, minute, their bases compressed and proportionally elongated, their sharp, conical points directed obliquely downwards. Surface of spine striated proximally by delicate longitudinal grooves, which become gradually lost towards the perfectly smooth apex. As usual, a rounded central cavity commences at the base and extends towards the apex.

It is rather remarkable that the Theory of the Permanence of Continents and Oceans has passed so comparatively unchallenged by geologists. I long since attempted to show that Mr. Wallace's supposition that the Chalk was a shallow and littoral sea deposit was untenable. In comparing analyses of chalk, as he does, with Atlantic ooze, no allowance whatever is made for the loss of iron from the body of the chalk by crystallization, nor for the segregation of silica into flints. The Chalk may have undergone so great a change in addition, since its upheaval vast ages ago, through the removal of some of its constituents by percolating water, that comparative analyses can only be of value when these losses are taken into consideration.

At Penyrhiwan, Clynnog, in the middle of fields, is a protruding boss of dark-coloured rock which has been well broken into, in order apparently to see whether it was available for making “sets” or pitching stones, which form the staple trade of the adjoining district. Its surface is well rounded, as if by glaciation. The boss consists of at least three varieties of rock. Most noticeable is a coarse-grained hornblendic one of handsome appearance, the glistening cleavage planes of the brown hornblende standing out from the remaining green actinolitic portion. a second variety is a fine-grained greenstone, which is separated from the preceding by a hard definite line, so that it may be taken to be of the nature of a dyke intruded into it.

There is an unfortunate Nemesis attaching to great discoveries and generalizations, which has not been sufficiently noticed. When men have been floundering about for years in a quagmire of confusion and difficulty, and some brilliant pen points out a clear waj' by which the tangle may be threaded,—a way which is so ingenious and simple that it at once seizes upon the current scientific thought, and compels the adhesion of everybody,—it inevitably produces a period of stagnation and for a while dwarfs inquiry. What is so palpably true and simple as the explanation of a very perplexing difficulty is taken to explain all the difficulty, and, for a while at all events, men's energies are devoted to bringing every apparently aberrant and stubborn fact within the new law or the new process; and every effect, however remote, is traced by a direct way or by a zigzag to the prime cause which has proved so fruitful. It is only after an interval, when men have digested and incorporated the new theory into their daily creed, and it no longer overawes them by its freshness, that they are in a mood to ask soberly whether, after all, too much has not been demanded from one cause,—whether, after all, the intricate and far-fetched explanations, which are necessary to connect that cause with effects with which we are familiar, is not illegitimate,—and whether we must not supplement it by some other cause, which has modified and altered its work, if we are to solve the whole riddle.

Proffessor Hull's criticisms (pp. 491–5 of this volume) on a former paper of mine on the “Classification of the Permian and Trias” lay upon me the burden of a brief reply. I may say that Prof. Hull seems to suppose that the task which I had set myself was more ambitious in its scope and aim than I was conscious of; it was not my purpose “to review the whole question of the relations of British Permian and Trias” in a paper which was limited by its title to the European rocks, and from which these systems in other parts of the world were intentionally omitted. My idea was rather to give to readers of the Geol. Mag. an opportunity of forming some judgment on the results which might be fairly gathered from a digest of the opinions collected from the various members of the “Sub-Committee on Permian and Trias.” taken along with the information which exists in the literature of this subject in England and on the Continent, more especially in Germany; and to raise discussion thereupon before the assembly of the Berlin Congressin1884.

The geology of the neighbourhood of Birmingham is one of more than ordinary interest, owing to the great variety of geological formations exposed within its area. Its rocky structure was investigated about thirty years since by the officers of the Geological Survey of Great Britain, and its several geological formations laid down upon their maps, and described in detail in their various explanatory memoirs. Some of these publications—notably the maps and descriptions of the South Staffordshire Coalfield—have subsequently become classic in the literature of Geology. Since these publications were issued, however, the science of Geology has made great advances, more accurate and detailed methods of research among the older rocks have been developed, and their application to the study of the strata of the Birmingham district has recently resulted in the detection of several most interesting facts which escaped the notice of the earlier investigators.