Without the slightest wish to interfere with the management, or any desire to criticize the past doings of Natural History Societies and Field-Clubs, we may be permitted, without any imputation of meddling, to suggest how much good work the forthcoming year may produce, through a little forethought and pre-arrangement. Spring time will now soon be upon us, and the time for field-excursions will have come on again. Would it not be well if the Councils of Societies organized their arrangements with a view to some practical ends?

In the districts of crystalline and metamorphic rocks, examples of transitional states bearing on the great origin-of-granite question might be designated as one of the topics of inquiry, and members solicited to search for and study examples, and to send notices of them to the Societies before the excursions were decided upon. In the districts of the Secondary rocks, examples of unconformability and thinning out, and the intercalation of special deposits, would also form a most valuable subject of inquiry.

Palaeontology, as such, should not be neglected: and by selecting given genera or families of fish, mammals, or mollusca, and tracing the ranges of species upwards and downwards stratigraphically through the separate beds of the various deposits of any geological formation or formations, the most valuable data for geological progress would be obtained; and contemporaneously with this investigation, another, devoted to the geographical extent at each horizon of the same species, should also be carried on.

A few months ago I sent to the British Museum a block of mountain limestone, perforated into deep cells by mollusks. It was met with on a limestone ridge three miles south-west of Ulverston, and first attracted notice by being brought to town to be employed for building purposes.

The perforations were found to be on the under-side of a projecting ledge, and were large enough for the fingers to be introduced upwards to the depth, in some, of three inches, the diameter being about seven-eighths of an inch. They were inhabited, at the time of the discovery (August), by the land-snails Helix nemoralis and Helix concinna.

Mr. Woodward, on receiving the stone, very kindly sent for my perusal a ‘Memoir on Perforations by Helices in the Calcareous Rocks of the Boulonnais,’ by M. Bouchard-Chantereaux. In this memoir the author states his belief that the cells are the work of Helices, and that the eroding action is performed by the foot, with the aid of an acid secretion.

Ever since I became familiar with the microscopic structure of the tongue of Helix, etc., I have always believed that it was so constructed for purposes of abrasion, either of stone or other hard substances; but I was not previously aware that the land-snails were, any of them, supposed to form for themselves hollowed, hybernating chambers in rocks.

Lamellibranehiate shells are the most abundant fossils of most rocks. Numerous in genera, and prolific in species, they are multitudinous in individuals, and the specimens vary. The study is not easy. It has little of the poetry of many other branches of natural history, and has naturally received less attention. But in each subkingdom specially, no less than in the animal kingdom generally, the law holds good that the lower the organization the longer is the duration in time. And so, important as the higher mollusca are in the analysis of rocks into their several zones, it is on the lower forms we rely in synthetical arrangements. The Conchifera readily divide rocks into Palaeozoic and Neozoic,—no form with a pallial sinus being known below the Lower Secondary strata; while, from the appearance in them of numerous new genera, no class of animals better marks the recognized systems into which fossiliferous rocks are grouped. It is indispensable both to the geologist and biologist to be familiar with the genera, and it is the object of this paper to render the principles on which they are identified more easy and exact.

That genera are practically realities every student knows well; as such the geologist and zoologist have to do with them. And it has elsewhere been shown that between hosts of groups intermediate forms can no more be found, than can intermediate wood fill the space between the forked branches of a bush. Accepting the fact, the question arises,—How may genera be known?

We shall, we trust, be pardoned for returning in this number, before we proceed onwards to Cuvier's works, to some omissions of old authors which have occurred.

The first of these additional quotations is from Scheuchzer's later work, published at Zurich in 1718, ‘Meteorologia et Oryctographia Helvetica,’ p. 336.

“Diluvian Birds.—Everybody can very easily conceive that all the birds, owing to their agility, could have escaped the waters of the Deluge, and it is therefore not to be wondered that even in the richest and best-assorted museums of arts and natural history, remains of the bird-kind are very seldom to be met with, or that they are, so to say, scarcer than a white raven. In Switzerland I have as yet found nothing; from the quarry of Oeningen I can show a well impressed bird's feather, which I have reproduced on page 14 of the Querel. Pisc.” This figure we give in our Plate IV. fig. 1.

The original passage follows below :—

“Aves Diluvianæ.—Es kan ein jeder ohnschwer begreifen, dass die Vögel, wegen ihrer Leichte, alle werden in denen Sündfluth-Wassern oben aufgeschwummen seyn, und sich desshalb nicht zu verwundern, wann auch in denen best-versehenen Kunst-und Naturalien-Kammern etwas von dem Vogel-Geschlecht überbliebenes so seltsam oder nock rarer ist als ein weisser Rab. In denen Schweitzerischen Landen habe noch nichts gefunden; aus den Oeningischen Steinbruch aber kan ich zeigen eine wol ausgedruckte Vogelfeder, welche habe abbilden lassen in Querel. Pisc, p. 14.”

A flint cast of a Mytilus has been obtained from the gravel of Barnwell, near Cambridge, by Mr. Percevall, B.A., Trin. Hall, and entrusted to me for description.

Form elongated and narrow, attenuated anteriorly, with valves deep, and longitudinally striated. The anterior outline of the lips is straight, that of the posterior side a gentle curve, which is somewhat straightened towards the apex. The shell is about three times and a half as long as wide, and widest below the middle. The lateral outline of the valves is lanceolate, the greatest height being in the anterior third.