MR. Teall,inhis very interesting and suggestive address to the Geological Section of the British Association at Nottingham, alluded to the composition of sediments (clays, etc.) as compared with that of older sedimentary rocks, and specially to the amount of alkali contained in them.

At the time he made his remarks I was engaged on some analyses of clays, with a view to gaining information on this particular point,inconnection with studies of clays and slates which I have been carrying on for some years, and on which I have published papers in this MAGAZINE on former occasions. The results of these analyses, and some considerations arising out of them, I propose to give as the first item of these present “notes.”

It is important, in the first place, to discuss those facts concerning the Earth which must be taken into account in any attempt to deal satisfactorily with the problem before us.

To a depth of about 80 feetinTemperate regions, the earth has its temperature determined by the seasons; being warmedinsummer and cooledinwinter.

In a previous paper on the Loess of S. Kussia, I endeavoured to discuss its character and origin, and to compare the facts observed with the results obtained by many students of the latest phases of our earth's history.inso doing I overlooked two articles on this subject, which appeared in the GEOLOGICAL MAGAZINE for 1882, and embodied the views held by Baron von Eichthofen and Sir H. Howorth respectively.

My endeavours to establish a genetic relationship between the Annelida and the Phyllopod Crustacean Apus led me, very naturally, to the study of the Trilobites. Specimens were kindly lent me by Dr. Woodward, F.R.S., Prof. Judd, F.R.S., and by Prof. G. B. Howes, it being my privilege at the time to be working in the Huxley Research Laboratory, which is under his direction.

Picking at the fossil with a steel point taught me, what every worker soon finds out for himself, that the limbs which, under such a dorsal shield, would probably have been thin-walled structures, could not be differentiated from the matrix by any such method. Was there, then, no mechanical method of revealing the undersurface? At first I thought, among other things, of a stream of water, mixed with emery powder, forced through a rose; this idea led, very naturally, to the sand-blast. a visit to the London Sandblast “Works” (58A, Gray's Inn Road) gave some promise. The proprietor was kind enough to express interest in the idea, and showed me blocks of granite which had been treated with the sand-blast, and in which the harder elements stood outingood relief. a very short application of one of the sand-blasts belonging to the Works to the under-surface of a Trilobite from the soft Wenloek cleared away a large portion of the matrix, and revealed a small area of the under-surface of the carapace completely cleaned.inthis specimen there was no trace of any under membrane having been cut through, and the carapace was probably the last remnant of a cast skin.

In the twentieth volume of the Bulletin de la Société geologique de France (p.277) a valuable paper with the above title was published. It contains three plates with a number of species, six of which are said to be new. That I cannot agree with all his conclusions Dr. Haug knows well, for, before the work appeared, the author kindly sent me copies of his proof plates for my opinion, and several letters passed between us on the subject; that he cannot agree with all my opinions on matters palæontological the author readily confesses in the present paper. Nevertheless in two cases of importance this paper does bring us more closely into agreement, as I will point out presently.

It not unfrequently happens in these days of superabundant scientific periodical literature that articles appear in which the authors, usually unwittingly, and generally from want of leisure, fail to give an adequate idea of the work of authors anterior to periods with which the writers are more specially acquainted. The injustice thus perpetrated can best be prevented by giving occasionally a brief resumé of work done in certain formations and in special areas during a given period.

While examining the dykes along the coast of Mourne in the company of Mr. R. Welch, I came across an additional example of intrusive variolite, the occurrence of which seems worth recording. The mass is,inthis case, a thin one, about 20 centimetresinwidth, narrowing and dying out as it is traced northwards; it runs in a somewhat sinuous course along the strike of the uptilted strata. Every other dyke that I have seen upon this richly favoured coast cuts across the Ordovician beds, and the present instance to the contrary may be only a lateral sheet-like offshoot from one of the familiar basalts.

Near the city of Matanzas,in Cuba, there is a beautiful valley called the Yumuri, of which the good people of the region are justly proud. Its interest to the geologist is unsurpassed in the island. At its entrance there is the most complete section of Tertiary rocks observed by me in Cuba. This valley is a record of the great erosion of the land during most of the Pliocene period, at the close of which it was partly refilled. The valley was reexcavated during the earlier days of the Pleistocene period, and suffered other changes, but it is the closing of the valley into a rock-basininalmost modern days of which I write.

Upon the northern side of the ridges, of which Pan de Matanzas is the highest point (1277 feet above tide), there are the remains of a former plain, which extended five or six miles to near the sea-shore, with an elevation of about 450 feet. Out of this plateau the Yumuri Valley has been excavated with a breadth of about three miles, and length ot five or six miles, with a further rugged extension of one of the tributary valleys teethe foot of Pan de Matanzas, as shown on Map (Fig. 1). The floor of the basin rises from near tide-level to considerable elevations in its upper part, where there are low ridges produced by the unequal washings of the tropical rains.

The relative position of post-Glacial Man to post-Glacial geology has been a rather neglected field of research. This borderland between the domains of the Archæologist and the Geologist appears to have been treated as neutral ground, yet entombedinit are the relics of Neolithic Man and the first evidences of the dawn of civilization. It may be alleged that the splendid results of cave exploration have given us a better idea of man's evolution from a savage to a civilized existence than could have been obtained from any other source. Whilst this must be admitted, cave research can furnish very little evidence of the great physical changes which went on outside such abodes. If for instance man can he proved to have been an inhabitant of Western Europe during the Glacial epoch, the gradual change of the climate from frigid to temperate may have had a powerful influence in modifying his habits and thereby assisting his development from the state of a rude savage to that of a civilized man. Deposits in caverns aid very little in this work. They are for the most part choked-up subterranean watercourses, and it follows that any deposits found therein may have been subjected to much disturbance. The most slender evidence derived from cave deposits is even by such distinguished geologists as Prof. Hughes and Prof. Boyd-Dawkins thought quite sufficient to determine the momentous question whether Palaeolithic Man was Glacial or post-Glacial. Prof. Boyd-Dawkins decides the matter in his “Early Man in Britain,” p. 192, in the following very summary manner:—

In a paper published in the Geological Magazine, September, 1894, Sir Henry Howorth expatiates on recent changes of the relative level of land and sea in support of his views on the Mammoth age and his diluvial catastrophe,inwhich there seems to me some very extraordinary confusion in the matter of geological chronology and sequence of events. The first paragraph reads as follows:—“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 a 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” (the italics are mine). The suggested relationship of these various events and their alleged catastrophic character, induces me to again enter this ever-expanding field of controversy.

In support of his thesis Sir Henry first refers to the subsidences which resulted in the separation of England from the Continent, and consequent extinction of the Mammoth. Assuming that the course of things was as stated, when it is further suggested that this event was contemporaneous with great dislocation of the Earth's crust, resultinginstupendous upheavals of mountain ranges in Asia and America, he attempts more than can well be proved.

I have to thank Dr. Callaway for the courtesy and good-humour with which he has received my criticisms on his paper in the December Number of the GEOLOGICAL MAGAZINE. Would that all controversial fencing were conducted with equally well-tipped foils.

My Roman soldiers,inparticular, have been received with a kindness that reminds me of the friendly meetings of the British and French officers in the Peninsular War during brief seasons of armistice. Indeed, one might almost go so far as to say that friendly intercourse with these Koman cohorts has imbued Dr. Callaway with a taste for military tactics, and has inspired him to perform a masterly change of front under cover of the active advance of a line of skirmishers.