In the general classification of the Palæozoic Rocks of North America, while we have carefully compared and attempted to correlate them with the greater divisions of the Silurian, Devonian, and Carboniferous systems of Great Britain and the continent of Europe, we have still retained the local names of formations, which to a great extent were given in the Geological Survey of New York. These names, like English local names, indicate a locality or region where the strata are well shown, and the characteristic features of the formation better developed than in other places. Several of these local formations have thus been grouped together as representing certain stages in the systems of formations as recognized above.

The first portion of this paper is devoted to a comparison of the Delta deposits of the Po, Mississippi, and Ganges, by means of the descriptions of the strata obtained from borings in their Deltas for water. The surfaces of these Deltas, and the alluvial plains above them, are compared together, with reference to their height above the sea and inclination, and it is found that a parabolic curve drawn through the extremities of each river, and through one point in its course, nearly represents its longitudinal section,-the greatest deviation being 30 feet in some of the largest Deltas. The Delta deposits are found to be coarser and more sandy near the bottom, and indicate more rapid rivers and greater rainfall at the earlier portion of their history.

In a republication of the papers by him which appeared in successive numbers of this Magazine, Mr. James Geikie has replied to the objections which I offered to his views, and also to the views of sequence which I myself advance, by asserting that the seaward ends of glaciers never float; and that my view that “wherever the ice-sheet rested there no deposit occurred, the material produced by its action incessantly travelling outwards to the ice-edge,” is a misconception.

In vol. ii. of his Flora Fossilis Arctica, Professor Oswald Heer has treated of the Fossil Flora of Bear Island, and shown that it belongs to the Lower Carboniferous Formation, of which it forms the lowest beds (named by him the “Ursa” beds), close to the junction with the Devonian. The Yellow Sandstone of Kiltorcan in Ireland, the Grauwacke of the Vosges, and the southern part of the Black Forest, and of St. John in Canada, belong to the same group. In the summer of 1870 two young Swedish naturalists (Wilander and Nathorst) discovered this same formation in the Klaas Billen Bay of the Eisfiord in Spitzbergen, and brought home fine specimens of Lepidodendron Veltheimianum, and Stigmaria ficoides. It has also been found in West Greenland, for Prof. Nordenskiold tells us that the Swedish expedition, which went to Disco in the course of last summer, to fetch the meteorite, weighing 25 tons, which he discovered at Ovifak in that island, has brought home fossil plants of true Carboniferous age.

In my last communication to the Magazine I made an attempt to correlate the Scottish Glacial deposits with the equivalent accumulations in Switzerland, Northern Europe, and North America, my purpose being to show that the same order of succession holds good in all those regions where the “Drifts” have been examined, and that in each case there is no proof whatever of any warm period having intervened since the deposition of the clays with Arctic shells and the decrease and disappearance of local glaciers. In the present and a subsequent paper I propose to treat of the superficial deposits of Ireland and England, more especially those of the latter country.

In my last communication. I gave some account of all the varieties of Arran pitchstones then known to me, and referring to other closely allied rocks, intimated an intention of describing them on another occasion.

All geologists, especially those who, like myself, are interested in the study of the Upper Tertiaries, are indebted to Mr. Prestwich for the valuable memoir upon “The Structure of the Cragbeds of Suffolk and Norfolk.” As the views propounded therein are somewhat novel, I purpose examining some of the points brought forward in their support.

Having recently had the opportunity of carefully investigating the genus Tentaculites, I was led to the conclusion that several fossils of diverse zoological affinities had been included under this head, and that the prevalent differences of opinion as to the systematic position of this genus might be thus readily explained (American Journ. of Science and Arts, vol. iii., no. 15, 1872). Originally founded by Schlotheim in 1820 (Petrefact. i., p. 377), Tentaculites, as its name implies, was believed to comprise fossils which were nothing more than the slender terminations of the jointed arms of Crinoids. Modern palæontologists have been divided in opinion as to whether Tentaculites was truly referable to the Tubicolar Annelides or the oceanic group of the Pteropoda— most recent authorities placing the genus in the latter class. In point of fact the difficulty has really arisen from the circumstance that two dissimilar sets of fossils have actually been included under Tentaculites; some of these being genuine Pteropods, whilst others are equally genuine Tubicolar Annelides. As all the typical species belong to the first group, it follows that the genus Tentaculites remains a Pteropodous one; whilst the Annelidan forms must be referred to new genera.

The older valley-gravels and cave-deposits of England contain, as every geologist knows, a remarkable intermingling of northern and southern forms of animal life. To account for this anomaly various theories have been advanced. There are few who do not admit, to begin with, that species such as the hippopotamus and the musk-sheep could not have lived side by side throughout the year in the same country. The conditions necessary for the support of the one would be fatal to the other. Some writers, therefore, have inferred that the occurrence of the remains of both these creatures in our superficial deposits points to former fluctuations of climate during the accumulation of these beds; while others hold that it only indicates a period of strongly contrasted summers and winters.

In the GeologicalMagazine for 1870 (Vol. VII., p. 267), I published a brief account of some burrows in Derbyshire; one group of. which, at the bottom of Miller's Dale, and on a scarp of rock which was probably artificial, appeared to me wholly irreconcilable with the theory which attributes them to the action of Pholades.

The term “Midford Sands” suggested by Professor Phillips for the Sands which occur between the Inferior Oolite and the Upper Lias Clay, gives us a very happy name, and one that has been long wanted for these beds; for hitherto although they have been called by many names, not one has been generally adopted. They were first discovered and studied, so Professor Phillips tells us, by William Smith, in the picturesque cliff which overhung his house at Tucking Mill, near Midford—a little hamlet about three miles south of Bath, and situated in one of those delightful valleys formed by the river Avon and its tributaries.

The principal specimens are several large slabs of brownish sandstone, bearing series of footprints in relief. Of the largest and most distinct series 40 to 50 footprints have been preserved, and are arranged in two rows, about inches apart. I may confine my attention in the first place to this series, as the most important of the whole.

During five and a half weeks' examination and study of the glaciated rock-surfaces and drifts of the south-central part of the Lake District, in June and July last, I was fortunate in meeting with many fresh and clear sections in diggings for house sites, drains, gravel-pits, tracks of unusually large rain-torrents, etc., which enabled me on some points to arrive at a more satisfactory classification of the drifts of the country than I had previously succeeded in devising.

It has already been sufficiently insisted that no warm or genial climate has intervened since the close of the Glacial epoch. The climate of Britain is milder now than at any other period subsequent to the re-elevation of our country after the last great submergence; our winters have been gradually growing less intense; Britain has slowly passed from an Arctic to a temperate condition of things. Mr. Dawkins accounts for the absence of the mammal-bearing drifts in Scotland and the upland districts of England by supposing that in post-glacial times all these regions were covered with snow and ice. This, however, is a rather exaggerated picture of post-glacial Britain. It is quite true that after the emergence of our country from the last great subsidence, a few local glaciers continued to linger on among our mountain valleys.

The researches in which the Author has been personally engaged during the last four years into the Temperature and other Physical conditions of the Deep Sea, combined with the information he has obtained from other sources, have led him to the knowledge of certain remarkable differences in regard to these conditions, which prevail between Inland Seas and the open Ocean. As these differences have a most direct and important bearing upon the distribution of Animal life, and as it would seem highly probable that similar differences have existed in all Geological periods, he thinks it important that Geologists, by being made aware of them, should be in possession of a key that seems likely to open the way to a rational interpretation of many Palæontological phenomena which are at present obscure.

My attention having been directed, during the construction of the Main Outfall Sewer at Birkdale, to the Post-Glacial deposits underlying the great plain between Waterloo and Crossens, and having, through the execution of numerous other works in the district, peculiar advantages for prosecuting investigations in Post-Glacial Geology, I am induced to lay before your readers several interesting facts, and also, as I venture to think, some important deductions therefrom.

These holes in the ice filled with water are in no way connected with each other, and at the bottom of them we found everywhere, not only near the border, but in the most distant parts of the inland ice visited by us, a layer, some few millimetres thick, of grey powder, often conglomerated into small round balls of loose consistency. Under the microscope, the principal substance of this remarkable powder appeared to consist of white angular transparent grains. We could also observe remains of vegetable fragments; yellow, imperfectly translucent particles, with, as it appeared, evident surfaces of cleavage (felspar?); green crystals (augite) and black opaque grains, which were attracted by the magnet. The quantity of these foreign components is, however, so inconsiderable, that the whole mass may be looked upon as one homogeneous substance.

In the Geological Magazine for December, 1871 (Vol. VIII., p. 570), we reported the return of the Swedish scientific expedition from the coast of Greenland, bringing home a number of masses of meteoric iron, found there upon the surface of the ground, the largest of which was said to weigh 25 tons. In the Report of the meeting of the Geological Society, Dec. 20th, 1871, contained in our present number (see page 88), we give some further particulars relative to this interesting discovery, which has elicited a letter from the Rev. O. Fisher (see GeologicalMagazine for Jan., 1872, p. 47), and a lively discussion at the Geological Society. We are indebted to R. H. Scott, Esq., F.R.S., for obligingly calling our attention to the account of the original discovery, more than fifty years ago, by Captain (now General Sir Edward) Sabine, of meteoric-iron in Greenland, recorded in the Quart. Journ. of Science, 1819, vol. vii., p. 79, with the analysis of the same, previously published, which we venture to think will prove acceptable information to many of our readers.—[Ed. Geol. Mag.]

In the Magazine for December I gave a brief outline of certain phenomena connected with the Scottish Till, the chief aim of my paper being to insist that beds of clay, sand, and gravel frequently occur in that deposit, and that we can no longer consider these as either insignificant or accidental.

Somewhat further to the west of Karsok, and about 50 feet higher up, occurs another similar stratum, containing a mass of graphite, so soft that it may be cut with a knife. This spot was not, however, accurately examined. A similar stratum of graphite imbedded in sand and clay occurs also at a very great height above the sea at Niakornet, but time did not admit of our visiting that spot.