Some time since, in the summer of 1884, Mr. Jex, a collector of fossils employed by Mr. Robert Damon, F.G.S., of Weymouth, obtained from the Lower Carboniferous Shales of Eskdale, a new and most interesting form of Merostomatous Crustacean belonging to the genus Eurypterus. It has been secured for the Geological Department of the British Museum (Natural History), and I now propose to submit a brief description of this very interesting specimen.

The term gneiss as generally used by geological writers signifies a rock of granitic composition in which a parallel structure in the arrangement of the constituents is more or less apparent. For our present purpose it is important to note that other plutonic rocks besides granite (e.g. diorite, gabbro, and peridotite) have their gneissose equivalents, so that, if we use the term gneiss in a structural rather than in a mineralogical sense, we may speak of diorite-gneiss, gabbro-gneiss, and so on. Now the parallel structure of gneissose rocks is of two kinds. It may consist (1) of a parallel arrangement of certain constituents (e.g. mica plates or porphyritic felspars), or (2) of an alternation of bands of varying chemical and mineralogical composition. It is agreed on all hands that a parallel structure of the first kind may be due either to the deformation of a mass of half-consolidated plutonic rock at the time of intrusion, in which case it is strictly analogous to the flow structure in many volcanic rocks, or to deformation produced by earth-stresses operating on the mass after consolidation.

Under the general terms of Primary and Original, given by Werner and others, to the early crystalline rocks, have been included various mineral aggregates which may be classed under three heads: 1. The great stratiform masses of aqueous origin, essentially granitic, and formed by slow deposition at the earth's surface, which I have called Indigenous rocks. 2. Those lesser crystalline masses which were formed under similar conditions to the last, but within veins or fissures in pre-existing rocks, and may therefore be called Endogenous. 3. Rocks resembling the last in their geognostic relations, and often confounded with them, but distinguished by the fact that they have come into their present positions not by deposition from solution, but by displacement in a more or less fluid or plastic state. These Exotic or erupted masses, whether ancient or modern, are in a sense Primary, since they sustain, in one way or another, intimate relations to the more ancient rocks to which this name was first given.

The question of the origin of the Archæan rocks is one of such great interest that it will not be thought unimportant on the one hand to record any facts that may bear upon it, and on the other to examine somewhat severely all the evidence that may be from time to time brought forward on the subject. Among the facts which may be adduced in support of the view that the Archæan rocks are altered sedimentary strata, the occurrence of breccias and conglomerates may well claim a foremost place; and a vast amount of superincumbent theory must rest on a very shaky foundation if there be any doubt whether some of those ancient fragmental beds be true conglomerates or not. The manner of occurrence, the mode of formation, and the character of pseudo-breccias and pseudoconglomerates become therefore questions of first importance.

At the present time the American geologists, both those of the United States and the Dominion of Canada, are at variance as to the groups the Archæan should be divided into; it is however unnecessary to enter into this controversy, as the strata may be conveniently grouped, as in Selwyn's map (1884), into Norians or Labradorians, excessively coarse gneiss or other granitic rocks; Laurentians, gneisa and granite; and Huronians, schists with subordinate gneiss.

In a paper read before the Geological Society in 1844, Sir Philip Egerton made known an interesting fossil Selachian from the Cretaceous beds of Mount Lebanon, which he named Cyclobatis oligodactylus, and referred to the Torpedinidæ, in consequence of its apparently unarmed skin and the resemblance between its general form and that of the familiar electric Torpedo. Six years afterwards Pictet figured and described a second specimen of the fish, adding some further particulars of the skeleton, and adopting Egerton's determination of its affinities. And quite lately, Mr. James W. Davis has made another contribution to our knowledge of the genus, by describing a larger and more robust species under the name of C. major. The fish is again relegated to the Torpedinidæ, and, so far as I have been able to discover, the same original determination has been universally adopted up to the present time.

Owing to the impossibility of making an accurate Survey of many of the flatter and Drift-covered portions of England, in the absence of sections, the light boring tools so extensively used by the Geological Survey of Belgium have been experimentally tried during the last few months in the Isle of Wight. The results arrived at are of so much interest that the Director has requested me to draw up this preliminary notice.

The Hempstead Beds, which were thought to be confined to the outlier at Hempstead Cliff and another of unknown extent in Parkhurst Forest, prove to be much more important, indeed they occupy about half the Tertiary area of the Isle of Wight.

The interesting note by Mr. Strahan in the Geol. Mag. for September, 1887, on explosive slickensides, reminded me of some similar phenomena which were not of unfrequent occurrence near Dent Head and Ribble Head in Yorkshire.

In the limestone quarry from which the black marble of Dent is procured the workmen found that, when they were quarrying the lower beds and struck the rock with a pick or bar, fragments flew up into the air with greater force than, could be due to their blow and in an unexpected direction.

In my paper on Crocodilia in the July Number of the Geological Magazine, pp. 310–311, I expressed my opinion that the characters given by M. Dollo in his description of the Belgian Bernissartia did not appear to me to afford grounds by which that form could be distinguished from Hylæochampsa, and I accordingly observed in a note that the onus of proving the distinctness of the former rested with its describer. In a note published on pp. 394–396 of the September Number of the Magazine, M. Dollo replies to this criticism, and shows conclusively that the Belgian form is entitled to specific, and very probably to generic distinction from the larger English one.