Griffithides, Portlock, 1883.—Outline oblong oval; glabella pyriform, gibbous in front, destitute of lateral furrows; basal lobes inflated; cervical lobe broad; eyes small, lunate, smooth; axial furrow clearly defined, outline of free cheek broadly triangular, outer posterior angle sometimes produced into a cheek spine. Thorax with nine segments; pygidium rounded, composed of from ten to thirteen coalesced somites.

Since geology entered the order of exact sciences, it has been acknowledged by all those, who thoroughly studied it, that the history of the earth is to be divided into three great periods, which have been called, after the faunas they contain, Palæozoic, Mesozoic and Cainozoic. Indeed it could not escape the eye of the palæontologist, that between the marine faunas of the Permian period and the Trias on one side, and the Chalk sea and the Eocene period on the other, there is a greater difference than between the animal world of any of the other periods. In the transition-period between Permian and Trias, Corals, Cephalopods, Reptiles, etc., underwent an astonishing change; thousands of forms seemed to have perished, thousands of new ones appeared; in the succeeding time, shortly after the commencement the fauna of the Mesozoic seas showed, on the whole, quite another stamp, than that of the Palæozoic seas. A quite undisturbed development seemed to have reigned from Silurian to Permian, and there seemed to have been a sudden interruption of that development during the Permian period. Again, there followed an era of the most quiet and peaceful evolution during the Triassic, Oolitic and Cretaceous periods, where the connection between the several marine faunas seems to have been an uninterrupted one; then, at the end of the Cretaceous period, the marine fauna underwent a new change. The dawn of a new time (Eocene) begins, thousands of forms again disappear to be replaced a second time by new ones, as had occurred during the Permian period. Again, the Cephalopods seem to have been the class against which a war of annihilation was directed, and in their place the Pelecypods and Gasteropods take the leadership in the new era. The Enaliosaurians having reached a high development die out entirely and the Crocodilians retire to the rivers. The Secondary fauna gives way to the Tertiary, bearing a thoroughly new stamp.

In the September Number of this Magazine, Mr. H. Keeping impugns the accuracy of my father’s view as to the shell-bed at Meadend, which it seems has now disappeared; and says that it was a slipped mass from a bed which, by digging, he found in situ higher up the cliff slope, “close under the gravel with all the Lower Headon Freshwater beds below it”; adding “that he wishes to be distinctly understood to maintain that it is the marine Middle Headon of the Geological Survey, and equivalent to the Middle Headon of Colwell bay, Headon hill, Whitecliff bay, and Brockenhurst in the New Forest.” As I am the only survivor of those who in 1843 worked at this bed, and upon whose discoveries in it my father’s description of it was based, I wish to put on record the facrs at that time, and vindicate my father’s accuracy.

In 1879 Mr. Sorby in his Presidential Address to the Geological Society published the result of his investigations into the question of the extent to which the mineralogical constitution of shells, etc., influenced their preservation as fossils.

Striking a radius of 40 miles from Southport, the line will be seen to intersect the sea-coast near the Silurian districts of Ulverstone in North Lancashire, and Colwyn Bay in North Wales. The succession in both cases is very similar, Denbighshire Grits and Flags of the one area corresponding in time to the Coniston Grits and Flags of the other; and just as the Silurians of the Lake District are overlaid by a fringe of Carboniferous Limestone, so the Silurians of Diganwy are overlaid by the Carboniferous Limestone of the Great and Little Ormes Head. Laid upon a floor of Silurian rocks, the Carboniferous Limestone may be regarded as extending continuously under the Irish Sea, and underlying the various Carboniferous and Triassic rocks now occupying Lancashire.

A few years since it would have been flat heresy to assert that very clear proof would be necessary before we could accept a crystalline schist as the metamorphosed representative of a rock of Palæozoic age. Yet at the present time many who have made a special study of this branch of petrology would not hesitate to go thus far, and some would even declare that we do not know of any completely metamorphic rock which is not of Archæan age. Certainly the stock instances of metamorphism in Wales, and especially in Anglesey, in Cornwall, in Leicestershire, in Worcestershire, have utterly broken down on careful study. Outside the English Geological Survey probably no person who can use a microscope believes that the schists of Anglesey are altered Cambrian, or that the slates of this age are melted down into the quartz-porphyry of Llyn Padarn. It is becoming evident that even the metamorphic fastnesses of the Highlands are in danger, and that at any rate even there the realm of “altered Lower Silurian” will be grievously curtailed. Startling facts are now and then adduced by the defenders of what we may call the ‘established’ (i.e. non-progressive) geology; fossils are said to have occurred in crystalline non-calcareous rocks, Calamites in gneiss, Trilobites in mica-schist, and so on; but those who are familiar with the molecular changes which take place in the formation of such rocks as these will require the clearest evidence before they can accept statements so antecedently improbable.

The remarkable conglomerate, called nagelflue, which fringes a considerable extent of the northern district of the Swiss Alps, and in places forms almost mountain masses rising some 5000 feet above the sea, has already received much attention from geologists. One might then fear to handle a subject almost as well worn as its pebbles. Still there are one or two points to which in the present state of our knowledge it may be worth while to call attention.