Shoetly after the great volcanic eruption at Krakatoa,inAugust, 1883, the Royal Society appointed a Committee to collect and sift the records of that remarkable outbreak and to study, the effects which appear to have resulted from it. The investigation of the volcanic phenomena and of the materials ejected from the volcano having been committed to me, I have been led to some conclusions of considerable geological interest, the full discussion of which could scarcely find a place in the report which has been published by the Committee. It is these general results which I propose to discuss in the following communication.

In various numbers of the “American Journal of Science,” the writer has given the more important characters of the skeleton of the Stegosauria, and has indicated the relations of this group to the other known Dinosauria. The discovery of additional specimens of Stegosanrus, one of them nearly complete, furnishes material to greatly enlarge our knowledge of the skull and dermal covering of this genus, and some of the new facts are given in the present article.

That many of the Palaeozoic limestones are more or less exten sively composed of the skeletons of various Invertebrate animals, sometimes in a perfect condition, sometimes more or less largely fragmentary, has long been known.incertain instances a microscopic investigation of these ancient calcareous sediments may fail to demonstrate the presence of organic remains, or may reveal but few of these. Thus there occur beds of lithographic limestone in the Palceozoic series which would seem to be simply of the nature of very finely levigated calcareous mud, the component grains of which were, however, doubtless derived, in the first instance, from the calcareous skeletons of animals.

Subsidences are by no means unusual amongst the arable lands in the Chalk districts of this county. No one, who has travelled in these parts, can have failed to notice the numerous holes and dells dotted about the fields in all directions, many of which have fallen in, or will do so,incourse of time. Nearly all of them mark spots where the Chalk has been dug up for chalking the land, which is then said to work better.

Elsewhere I have shown that metals under certain conditions when subjected to changes of temperature undergo permanent deformation. Thus sheets of lead ridge up and fold even under the influence of atmospheric changes, as may be seen by the examination of any old lead flats or gutters. The cumulative effect of small but repeated changes of temperature is very striking; and I have used it in illustration of what I conceive to be the true explanation of the ridgings up of the earth's crust called mountain ranges. The examples given of the effects of alternations of temperature are mostly in metals, but I have also shown that other materials not ductile are affected in the same way. in a lesser degree.

Writers on Fossil Corals seem to ignore the existence of Corals in our later Tertiary formations. They are certainly not common. The following reference and species have come under my notice: Caryophyllia clavus, Scacchi var. boreal is, Flem., Lancashire drift (see Geologist, 1843, p. 124). Caryophyllia clavus var. Smithii, Stokes, Kaised beach, Portrush, Co. Antrim (Portlock, Geol. Londonderr, etc.). Sphenotrochus Wrightii, Gosse, from the Clyde beds, by Messrs. Crosskey and Robertson. to these I may add a fine calice of the Norway branching Coral Lophohelia prolifera, Ed. and H., from the interglacial sands of King Edward, N.B., and a single young example of Sphenotrochus Macandrewanus, E. and H., from the Raised sea-bed, Largo Bay, Fife.