Comparatively few of the many persons who visit our larger Museums, and stop to examine the fossils exhibited in the cases, have any idea of the time, labour, care, and mechanical skill which many of them require ere they are ready for the palæontologist to interpret and describe, the artist to delineate, or made sufficiently intelligible for public exhibition. The first operation, and one requiring considerable care, is the exhumation of the fossil remains from the stratum of gravel or clay, or from the siliceous or calcareous rocks of various degrees of hardness, in which they may have been imbedded and preserved. Then the hardening of the bones—for these remarks apply more especially to the remains of the larger Vertebrata—which are generally found much broken, and, unless thoroughly mineralized, in a more or less friable and brittle condition. Next there is the fitting and cementing together of the pieces, which are frequently numerous, and of such as have been imbedded in a rocky matrix, the careful development by hammer and chisel from their incasement of stone: all of which operations necessarily involve a large amount of skilled labour.

As missiles are falling thick like hail upon Mr. Judd since his challenge to the Glacialists, I take the opportunity of putting together a few notes, made during an Alpine journey last summer, which would have been published sooner, had more time been at my disposal. The lower parts of the Gorner, Arolla, Des Bossons, Des Bois, and Argentière Glaciers were carefully studied, but others received passing attention.

Of all the physical features of our continent, that which most powerfully arrests the attention is the noble chain of the Alps, with its wide-spreading system of subordinate mountain-ranges; and among the series of grand events, which by the researches of the geologist are demonstrated to have taken place on this our own portion of the globe, there are none more striking and conspicuous than those manifestations of subterranean forces to which the vast mountain-masses in question owe their origin.

Upper Silurian.—At the close of the Lower Silurian, as already stated, changes of considerable importance took place in some of the areas which had undergone depression. The sea-bottom was now raised in parts of Western Europe, and in North America, and islands of some extent formed. In Europe the most important were those in North Wales, Shropshire, Cumberland, the South of Scotland, and in Nassau. It is probable also that one or more extended along Southern Europe, from Portugal into Spain, etc., but the evidence concerning this is as yet imperfect. In America, according to Logan, Dana, etc., the principal parts raised at this time were the Green Mountain regions, and the ridge extending from Lake Erie over Cincinnati into Tennessee. These American ridges appear to have been raised to a great height, and to have remained afterwards in part dry land, even to the close of the Palœozoic. The islands in Europe were raised only to a small height above water-level, and were probably all again submerged by the close of the Upper Silurian.

There is a fine exposure of the “Lower Greensand” in a railway cutting by Sandy Station on the G.N. and L. & N.W. Railways, presenting a nearly vertical section 50 or 60 feet in height. It consists almost entirely of clean sand, in parts falsebedded, and more or less coloured throughout by the presence of oxide of iron. The colour thus imparted to the sand varies from almost pure white, at the lower part, through shades of grey and yellow, to a deep rusty brown. There are here and there layers of hard ferruginous concretions in tabular, spherical, and many other forms, presenting a feature hitherto (so far as the writer is aware) unnoticed. This is a gradual passage from soft iron-stained sand to hard complete concretions, exhibiting the various stages in the process of their formation.