We are in possession of so little accurate information concerning Foraminifera of pre-Carboniferous age, that any contribution to the knowledge of the subject, however insignificant it may of itself appear, has a very distinct value. The only notices of pre-Carboniferous examples of the genus Lagena hitherto published occur in a provisional list of Microzoa drawn up by Professor T. Rupert Jones, F.R.S., and appended to a paper by Mr. J. Smith of Kilwinning, “On a Collection of Bivalved Entomostraca and other Microzoa from the Upper-Silurian Strata of the Shropshire District,” in the Geological Magazine for February, 1881; and in a brief allusion to the same specimens in the “Report on the Challenger Foraminifera” (p. 449, etc.); but iu neither case is the notice accompanied by any details.

The brief paper on the “Stratigraphical Succession of the Cambrian Faunas in North America,” communicated to Nature of Oct. 4, 1888, will have been read by British students of the Geology of the Lower Patæozoic Rocks with especial interest and satisfaction, as it puts an end to a controversy between European and American Geologists, and brings into harmony the sequence and palæontology of the Cambrian faunas on both sides of the Atlantic.

The genus Actinoceras was founded by Bronn in 1837, upon Dr. Bigsby's figures in the Transactions of the Geological Society; the chief distinguishing character being the possession of a large, dilated, and segmented siphuncle, filled with radiating deposits. The presence of a smaller internal tube with tubuli radiating therefrom and communicating with the septal chambers through the wall of the siphuncle. had not then been observed.

In view of the active discussion of the problems of earth-movement and mountain-growth now current, certain fundamental definitions, growing out of the discrimination of processes commonly confounded but really distinct, seem to be timely.

The various processes with which the geologist has to deal fall naturally into two principal and antagonistic categories and five subordinate and supplemental categories; and each category, great and small, comprises two antagonistic classes of movements or agencies.

More than forty years ago the detached teeth of Hybodont Sharks were recognized by Reuss in the Cretaceous rocks of Bohemia, and these were referred to the genus Hybodus under no less than eight specific names. About twenty years later, evidence of a somewhat similar Selachian was discovered by Mr. William Davies and Mr. S. J. Mackie, in the Lower Chalk of Kent; and the cartilages of the jaw, with a few teeth, were briefly described by the last-named geologist under the name of Hybodus dubrisiensis. In 1886, the present writer pointed out, from more recently discovered specimens, that the English Cretaceous species was more specialized in every respect than any of the typical forms of Hybodus; and quite lately it has been proposed to regard this fossil as generically distinct, with the new name of Synechodus.

During a recent visit to the University Museum at Oxford, I observed in the Grindrod Collection an interesting small fossil apparently adding to the known fauna of the Ledbury Passage Beds a remarkable type of fish, hitherto only met with in the Middle and Upper Devonian of the United States. Through the kindness of Professor Green, I have since had the opportunity of studying this specimen in London; and it is shown, of twice the natural size, in the accompanying Woodcut. It may be regarded as an imperfect example of the so-called “intermandibular arch” of the extinct ganoid, Onychodus, described by Prof. Newberry from the Corniferous Limestone of Ohio, and the Chemung Group of Delaware County, New York.

I Have been very much interested in reading Mr. Russell's two communications published in the Geological Magazine for August and September last. The analogy which he draws between the history of the Dead Sea valley and that of some of the lake valleys in the western part of North America is instructive as showing how similar physical features can be accounted for on similar principles of interpretation over all parts of the world. Mr. Eussell very properly draws attention to the paper by his colleague Mr. G. K. Gilbert on “The Topographical Features of Lake Shores,” in which principles of interpretation of physical phenomena are laid down applicable to lakes both of America and the Jordan-Arabah valley. With some of Mr. Russell's inferences regarding special epochs in the history of this valley I am very much disposed to agree; more particularly in reference to the mode of formation of the Salt Mountain, Jebel Usdum; or rather, of the salt-rock which forms the lower part of its mass. If this interpretation be correct, it removes the difficulty of understanding why the rock-salt is confined to one small corner of the lake, which, at the time the salt was in course of formation, was vastly more extensive than at present.

These specimens were collected in Socotra, near the coast, by Colonel M. Gosset, and were sent to Prof. Rupert Jones. By the kindness of Prof. Bonney I have been allowed to carry on the examination of the rocks, at University College, in connection with the Somali specimens already described.

The nomenclature of the fishes of the Old Red Sandstone of Great Britain, with the exception of the Cephalaspidæ, revised some years ago by Professor Lankester, is at present in a very unsatisfactory state. A vary large number of the species named by Agassiz, as well as by McCoy, were undoubtedly founded upon deceptive characters, due partly to different modes of preservation in different rocks, partly also to those apparent variations in external form, which are inevitable in such ancient fossil fishes devoid of a fully ossified internal framework, without which the original outline cannot be expected to be constantly preserved. In specimens from one locality the external ganoid surface of the scales may be well shown, in those from another it may be constantly hidden or obscured, while the proportional measurements in the very same species may vary infinitely, by the fish being lengthened out, or shortened up by changes, which have occurred after death or during the consolidation of the enclosing rock. These and kindred sources of fallacy can only be guarded against by long experience in deciphering such remains, coupled with the examination of an immense number of specimens.

In the October Number on page 434, line 27 from top of page, for “exopodite” read endopodite.”