of Haugh Wood has been left by natural causes, as if it were a huge artificial entrenched camp, with two encircling mounds and two circumfluent valleys.

Mr. Symonds says that the term "Valley of Elevation" does not convey an adequate idea of the wonderful geological history portrayed in the valley of Woolhope. The central dome of Haugh Wood is occupied by the May Hill rocks with Pentameri and encrinital stems, the central nucleus being no doubt composed of some far older formation, probably Cambrian or Syenitic rocks. Around the May Hill beds the Woolhope limestone circles dip away on all sides under the Wenlock shale and limestone, and these again under the Ludlow rocks and the Old Red Sandstone.

The Woolhope district in its extension from Marcle to Mordiford may be denominated as an elongated pear-shaped mass of Upper Silurian deposits, which were elevated through the overlying Old Red Sandstone, and were then denuded down to the May Hill beds at the domed Haugh Wood.

The district offers a peculiarly instructive history to the physical geologist, for when, after studying the rocks around and across this area, he beholds the shales hollowed into valleys, and the tilted limestones standing out like the walls of an encampment, he cannot doubt that the stratified masses now occupying hills far asunder, were once parts and portions of strata which were formerly conterminous and joined together, all of which must have swept nearly horizontally over the rocks which now form the dome of Haugh Wood. It is evident that earthquake agency upheaved the Silurian rocks through the overlying Old Red deposits, but that great power, denudation, has also wrought with tremendous force, for scarcely a fragment is left of the rock masses that once formed the roof, or overlying crusts of the elevated strata, which must have been denuded and carried off as the elevatory movement was gradually progressing.

Some geologists have believed that the gradual action of the sea has produced the wonderful results of erosion which present themselves on the surfaces of rocks of all ages. But if we look to the agency of present seas we know that the deep ocean never erodes, and that, on the contrary, perfect tranquillity reigns at its base. If, then, denudation in our time is produced only by breakers or by waves acting on coast-lines which have, we know, a wasting and denuding power over limited regions, how account for the perfectly clean sweep which has been made of wider tracts? With the exception of ordinary submarine currents to which many continents must have been subjected, what more natural method of explaining these facts than by referring them to the translation by vast bodies of water suddenly put in action by those upheavals of parts of the earth of which we have clear evidence? Judging from the fact that marine gravel and shells do often lie in terraces at different altitudes on the sides of our mountains, must it not be admitted that each of the upward sudden movements leaving such a terrace must have given rise to waves of such magnitude and force as would sweep over and scour the low tracts, destroying land animals in their course, and mixing them up with those of aquatic creation? How explain the mixture of bones of all sorts of animals except by some such catastrophe! Murchison says emphatically, "Let not beginners in geology be led away by those who, deriding convulsionists

and catastrophists, repudiate data, which many men who have passed their lives in the study of the dismemberments of the rocks think are inexplicable, without appealing to much more powerful causes than any of which history records an example. What agency except that of very powerful currents of water could have removed every fragment of the débris of the Silurian Valley of Elevation of Woolhope, and scooped out all the detritus arising from its destruction, from the circling depressions, the central dome, flanking ridges, and former cover of those Silurian strata? And if the water had not been impelled with great force, caused by the sudden uprising of these rocks from beneath the Old Red Sandstone, what other agency will account for so complete a denudation, the broken materials having only found issue by one lateral gorge, which was, we see, opened out by a great transverse fracture of the encircling ridges?"

Leaving St. Ethelbert's Camp, the members descended, some by the way of the landslip from Tower Hill of three acres of land with forty oak trees, which occurred in the year 1844, the remainder through Perton lane, where the geologists obtained, either in the hard nodules of the Middle Ludlow or Aymestrey formation in the exposure in the cutting, or in the grand exposure of the same formation some sixty or seventy feet high, in the quarry upon the left hand, specimens of the following fossils :-Atrypa, Bellerophon, Orthoceras, Rhynconella, Strophomena, etc. The conveyances were rejoined near Perton farm, and the journey homewards resumed, until a halt was called at Mr. Forman's farm at Bartestree, whence a walk across the field brought the party to the Loosehill Quarry close behind the Bartestree Convent, the property of Mr. William Henry Barneby.

When the members had examined the metamorphosis of the Old Red Sandstone by the eruption of Greenstone or Diorite, the Rev. J. D. La Touche gave the following description of igneous rocks:-"Much attention has of late years been given both to the materials of which igneous rocks, such as those before us, are composed, as well as the conditions under which they have assumed their present form. Studied in the light which existing volcanoes throw upon the subject, we find that they may be classed under three divisions. First, the ashes

and scoria which are blown from the crater, and which are afterwards consolidated into beds, either under water or on land; secondly, molten matter, intrusive in the cracks and faults of pre-existing sedimentary, and sometimes volcanic, rocks; and thirdly, great sheets of lava spread over the surface. We have an example here of the second of these three classes. This mass of Diorite, as it is called, was once in a molten state, and has clearly left the traces of its intense heat on the Old Red Sandstone wherever the point of contact may be observed, baking it .and altering its character. Not only so, but its very composition tells the same tale, since, as Professor Judd and others have pointed out, the central portions of the mass are more coarsely crystalline than the parts which are in contact with the sandstone. This may be easily understood if you consider what takes place were you to dissolve a quantity of carbonate of potash or other crystallisable material in water. If the solution be allowed to cool and evaporate very slowly, large crystals will be formed, whereas if the cooling takes place very rapidly they will