In previous articles the writer has given the more important characters of the order Sauropoda. A volume on this group is now in preparation, and the illustrations (90 plates) are nearly completed. One of these is a restoration of Brontosaurus, which has so many points of interest that a reduced figure is here presented. Several new characters of this group are added, some of which will be of interest to comparative anatomists.

In the August number of this Magazine, Mr. Howorth has challenged the view which I have advanced of the origin of the Loess (in common with the intrusive cave earth, the Warp of Trimmer, and the Trail of Fisher), from the slide of the upper and annually thawing layer of the permanently frozen soil, in the parts beyond the limit of the land-ice during the major and minor glaciations; or, as regards areas covered with sea during the major, from this process during the minor glaciation only.

Of the various theories that have been advanced from time to time to account for the origin of jointed structure in rocks, the one that seems to find greatest favour amongst geologists of the present day is that put forth in M. Daubrée’s Etudes Synthétiques de Géologie Expérimental, vol. i. p. 300, et seq., wherein their formation is ascribed to the effects produced by torsion. No one can read the account of M. Daubrée’s experiments without feeling convinced that the deductions he has drawn will enable us to account for the origin of many forms of joints in a manner that leaves little or nothing to be desired. The mere fact that some of the foremost leaders of geological science at the present day hold views on this subject practically identical with his, will, doubtless, be generally regarded as a sufficient reason for accepting M. Daubrée’s theory as one that has supplied a definite and satisfactory answer to the much-vexed question of the origin of joints in general.

With the increase of population and the simultaneous pollution of rivers in this country, the question of water-supply for the purposes of human life becomes every year a more serious one. Among the many schemes which have been advanced for the supply of London with water, it has been proposed by a high authority to bring the Bagshot Sands of the London Basin under requisition. These strata, covering, as they do, a considerable area at no great distance from the metropolis, and being for the most part of a porous character, would appear to form a convenient reservoir of water, since they contain stored up within them a large portion of the rain-water which falls on portions of Berkshire, Surrey, and Hants. The water obtained from these sands, either from surfacesprings or deep wells, is free from calcareous hardness, but is highly charged with salts certain of iron, which, by oxidation on exposure to the air, yield an ochreous red precipitate, the nature of which seems generally to be but imperfectly understood. The inconvenience, however, which results, in the turbidity of the water after no great exposure to the air, and the rapid corrosion of iron pipes in which it is conveyed, are facts with which all inhabitants of the Bagshot country are only too familiar. The fact that this property of water drawn from the Bagshot Sands varies greatly according to the portions of those strata which furnish it, does not however appear to be so generally known. Recent difficulties in connection with the water-supply of our own particular district have forced the matter upon my attention; and as I have been able to arrive at some pretty definite results from the investigations in which I have been engaged for several months past, it has occurred to me that, as forming a subsidiary subject to geological science, they may be of interest to readers of the Geological Magazine.

Let us move on again. The rolled gravels of Central and Southern England are divisible into two well-marked varieties, which were well discriminated, as Professor Phillips says, as long ago as 1815 by Dr. Kidd, and separated by him into a hill group and a valley group.