Many years ago, and before I entered on my duties in the Edinburgh Museum, the late Mr. C. W. Peach pointed out to me a specimen in the Hugh Miller Collection, which he was inclined to consider as new. It was a Cromarty nodule with dislocated remains, including a dorsal and a pectoral spine, of what was apparently a Diplacanthns of unusual size.

In some recent papers published in the geological magazine, I have endeavoured to show that at the close of the Mammoth age there was a very considerable dislocation of the earth's crust, and that a consequence of it was the upheaval of some of the highest masses of land on the earth, including the massive mountains of Asia and the American Cordillera. I now propose to show that (as is à priori probable) there was a concurrent collapse or sinking of the ground over large areas, which, as in the corresponding upheaval, was very rapid, if not sudden.

I wish to make some corrections and additions to my recent paper on the Tertiary insects from Gurnet Bay, and to mention others from older formations. I have recently had an unexpected and gratifying visit from my friend Mr.Scudder, the eminent American palæ-eutomologist, and if I had been aware sooner of his coming to England I should have deferred my notice of some of our British Tertiary Arthropoda until he had examined the large and varied seriesinmy Collection.

In the year 1878 there was a short controversy between us respecting these beds in the pages of this Magazine. Since that date we have both enlarged our knowledge of the beds at the junction of Chalk and Greensand, and recently we have had an opportunity of meeting at Seaton in Devon, and of examining the Whitecliff and Beer Head sections together. The result of this and of friendly discussion is that we have both modified our views and have come to an agreement on the most important points about which we differedin1878. Under these circumstances we think it will save trouble and facilitate future enquiry if we jointly express our present views on the subject so far as we are in agreement.

1. Chloritic Marl.—As far as we can ascertain, this name was first applied to certain beds at the junction of the Chalk and Greensand in the Isle of Wight It was subsequently adopted by Prof. E. Forbes, for a bed which occupied a similar position in Dorset, and has since been used for any bed lying at the base of the Chalk Marl and containing fossils and green grains.

The occurrence of a fish generically identical with Eurycormus of the Bavarian Lithographic stone, in the Upper Jurassic of England, has already been indicated by the discovery of a well-preserved head with some anterior vertebras in the Kimmeridge Clay of Ely. Only one specimen, however, has hitherto been recognized; and during a recent search for further evidence of the fish among British fossils the present writer has thus been gratified to find two more examples in the collection of the British Museum.

This paper deals with the species which are considered to belong to the genus Cymbites, and the reason for placing Paroniceras, Bonarelli, as a synonym. A few notes are added concerning Agassiceras, which is also affected; and a description of the little-known species Agassiceras Colesi (J. Buckm.) is given.

Amongst the rocks whose original structures have been more or less deformed by metamorpbic agencies the geologist very commonly meets with curious eye-like inclusions of mineral matter, which are generally known by the name of augen. Close investigation of a large series of rocks exhibiting these eyes brings to light the fact that under this name are classed two essentially different kinds of structure. in the one, the kernels or eyes are manifestly the unsheared portions of the rock, whose sheared portions constitute the schist that envelops the eyes. in the other kind of augen structure the eyes consist of crystalline minerals, whose development as such is shewn to be posterior to the shearing to which the matrix has been reduced, by the fact that the eyes of crystalline matter have not participated in the shearing, but are bright and generally unfractured throughout.

Italian geologists have made several valuable contributions to our knowledge of the Jurassio strata of their country. Unfortunately some of their works are not known here as they deserve to be, and seem difficult to obtain. At the same time I have to acknowledge with thanks the receipt of some valuable memoirs which have been of particular service; and one of the latest arrivals is the present pamphlet.

Mr. A. Vaughan has honoured with a criticism my exposition of the physical principles upon which my Theory of the Origin of Mountain Ranges is founded, which appearedinthis MAGAZINE last May.

Had it not been that much of what I have written seems to have been misapprehended, I should probably have refrained from comment and left the two papers to speak for themselves.

There are signs accumulating everywhere that the views so logically pressed to their conclusion by Hutton and Playfair, and by a great catena of geologists, since the appearance of the first edition of Lyell's “Principles of Geology,” have received a certain check; and no one can read the works of the great Continental geologists without seeing that there is a tendency to reconsider the position, and to hark back to the views of another school of teachers.

In the February Number of this Magazine, Mr. Hatchings announces that he has identified as Cordierite the mineral which constitutes the conspicuous “spots” in the metamorphosed slates of Wasdale Beck near the Shap Granite.inthis connection, it may be of interest to record another occurrence of the same mineral, discovered by Mr. Marr and myself a year or two ago. It is in the metamorphosed Skiddaw Slates of the Caldew Valley in Cumberland, the locality of our specimens being south-west of the farm of Swineside. The cordierite occurs there in crystals of quite irregular shape, charged with various inclusions, original and secondary, and stained with limonite.

Until very recently it was thoroughly recognised that in post- Tertiary, viz., Pleistocene or Diluvial times, there occurred in Switzerland, as elsewhere, two glaciations which covered the Alps and the greater part of the Swiss lowlands, and between which intervened a genial or interglacial period. The repeated advance of Swiss glaciers was first established by Escher von der Linth and Heer, more especially upon the evidence of the lignite slate deposits near Durnten and Wetzikon, which fringe the edge of what was at one time the Limmat and is now the Glatt valley, to the N.E. of Zurich, and were formed during the interglacial period referred to.

In a cutting of the Seacombe Branch of the Wirral Railway at the present moment is to be seen a deposit which cannot be other than a glacial shore. It is about 18 inches thick, covered by a bed of Boulder-clay some 8 feet thick, and has been exposed by the cutting for a distance of 16 chains running south-east and north-west, to the south-east of the point of intersection of the Railway with Poulton Road. The rise is 16 feet in this distance at a regular up-grade towards Poultou Road, and the average level about 60 feet above O.D. Transversely to the Railway it is about level, and over the whole of the area—1056 feet by 30 feet=3520 superficial yards—the deposit occurred and was excavated by the steam navvy. The bed is composed of pretty clean sand with some small gravel, and is crowded with shell fragmentsinall stages of decay. It is precisely like a modern beachinconstitution, extent and slope, but what renders the fact more certain is the great quantity of clay balls or boulders mixed with the sand. These balls are covered over their surface with small gravel, shells and sand, picked up as they rolled about on the beach, just like the mud balls we find on the shore at Crosby at the present day. On being cut into with a knife these clay balls are seen to be formed of ordinary compact brown Boulder-clay, and they are pretty hard. The contractor, Mr. Davies, who is much interested in the geology of the cutting, tells me that these clay balls are found all over the area in great profusion, and as far as I tested the bed, which I did in at least half-a-dozen places, I found the statement correct. He also informed me that the bed is underlain by silt, but it has not been tested more than a few feet deep. I picked up and brought away about twenty clay balls varyinginsize from 3 inches down to ¾ inch diameter, some of them being spherical and others ellipsoidal inform.

Mr. Deeley tells your readers that he has recently been to the summit of Mont Blanc, and has been studying the difference between névé and glacier ice. This is interesting; but we thought that a great many people had done the same thing during the last hundred years, and we thought that one of them, Forbes, had studied the famous Mountain and the phenomenoninquestion to good effect, not in a casual visit to the Alps, but in the course of many years of patient labour. Among other things we also thought he had shown that in a viscous body like ice, the slope of the upper surface necessary to make it begin to move is the same as the slope which, would be required to induce motion in the ice if its bed were inclined at an angle. He further collected considerable evidence to show what the least angle is upon which ice will begin to move. This is the slope, the least slope, available. It is nothing less than astounding to me that anyone should venture to postulate a Scand in avian ice-sheet in the North Sea until he had considered this necessary factor, and how it would operate.

The Scand in avian ice-sheet was, I believe, the invention of Croll, who, sittinginhis arm-chair and endowed with a brilliant imagination, imposed upon sober science this extraordinary postulate. He did not dream of testing it by an examination of the coasts of Norway, or even of Britain, but put it forward apparently as a magnificent deduction. All deductions untested by experiment are dangerous. Thus it came about that the great monster which is said to have come from Norway, goodness knows by what mechanical process, speedily dissolved away on the application of inductive methods. Of course it still maintained its hold upon that section, of geologists who dogmatiseinprint a great deal about the Glacial period before they have ever seen a glacier at work at all; but I am speaking of those who have studied the problem inductively. First Mr. James Geikie, a disciple of Croll, was obliged to confess that this ice-sheet, which is actually said to have advanced as far as the hundred-fathom line in the Atlantic, and there presented a cliff of ice like the Antarctic continent, never can have reached the Faroes, which had an ice-sheet of their own. Next Messrs. Peach and Home were constrained to admit that no traces of it of any kind occur in the Orkneys, or in Eastern Scotland. They still maintained its presence in the Shetlands; however, this was upon evidence which is somewhat extraordinary. I do not mean the evidence as to the direction of the striation, which was so roughly handled by Mr. Milne-Home, but I mean the evidence they adduce that the boulders found on the islands are apparently all local ones, and that, contrary to the deposits of glaciers, they diminish in number as we recede from the matrix whence they were derived.

The discovery of an Ammonite (Oppelia subradiata, Sow., from Dundry, now in the British Museum) with the Aptychus in situ closing the orifice, would seem sufficient to set all doubts at rest as to the true nature of that body, viz. that of an operculum. Many of the writers on the continent, however, have not seen that specimen, which unfortunately is unique, and are inclined to attribute to the Aptychus other offices, because:—

Dr. H. C. Mill has recently made elaborate bathometric surveys of the principal English lakes, and whilst taking the soundings he has collected a series of samples of the bottom-deposits, for the purpose of microscopic study.

At the request of Mr. Marr I undertook a careful mineralogical examination of these samples, and, though nothing very striking or specially interesting has resulted from the work, it may be worth while to record in the Geological Magazine the fact of such an examination having been made, and to state the mineralogical and other observations noted.

The Woodwardian Museum has for many years contained a fine series of Skiddaw Slatefossils.in1890 this was increased by the addition of many specimens obtained by themembers of Prof. Hughes' Long Vacation party, and immediately afterwards the University acquired, by donation, the valuable collection of the late Mr. Kiusey Dover. Prof. Nicholson has also presented a large number of Graptolites. When time permits, I hope to be able to describe our unrivalled collection of Skiddaw Slate fossils; mean-while, a few notes on the distribution of these organisms will throw such light on the development of the Skiddaw Slates as is required for the elucidation of the detailed structure of the district, a task which Mr. Harker and I shall attempt to perform ere long.

Having made my first acquaintance with that puzzling series of strata which bridges over the vast interval of geologic time between the Carboniferous and the Jurassic in the Nottingham district during a residence of eight years in the good old town (see Proc. Geol. Assoc. vol. iv.; also Quart. Journ. Geol. Soc, November, 1875), the meeting at Nottingham seems a fitting occasion for summarizing the results of further work in connection with those rocks, as opportunities have offered, during the last twenty years.

The district of Carrock Fell,inCumberland, is one richinvarieties of intrusive igneous rocks. Those on Carrock Fell itself, while probably belonging to one period of igneous activity, fall under three or four heads, which can be arrangedinchronological sequence, as follows:—

(i.) a large intrusion of gabbro generally laccolitio in character.

(ii.) a granophyre, also forming laccolitic bodies, but with associated dykes and veins which traverse the gabbro.

(iii.) a diabase or gabbro, not essentially different from the first intrusion, but injected later and under somewhat changed conditions.

(iv.) a large number of dykes and veins of intermediate to basic composition.

These last are found traversing all the other rocks, and therefore, if we are justifiedingrouping them all together, they represent the latest intrusions in the neighbourhood. They vary from straight dykes two or three feet wide to narrow and rather tortuous veins not more than an inch in width.

I have recently presented to the Geological Society an account of the larger intrusive masses of Carrock Fell,1 and I originally intended to include also the minor dykes and veins alluded to. This purpose I abandoned in view of the multiplicity and variety of rocks which they include, but some of the specimens examined seem worthy of a brief notice.

I am much obliged to General McMahon for criticising my recent paper in the Geological Magazine (Dec. 1893, p. 535) on the “ Conversion of Chlorite into Biotite,” because I have been puzzled to know the exact nature of the opposition to my views on rock-inetarnorphism at Malvern, and I have been haunted by the fear that perhaps after all I might have overlooked something fundamental. Happily my curiosity is now gratified, and my fear is removed, so far as one important branch of the enquiry is concerned. As my critic is so good a chemist, I may conclude that the worst has been said that can be said from the chemical point of view.