Sir Andrew Ramsay has described the Coal-fields of the Forest of Dean, Somersetshire, and Bristol as outliers of the great Coal-fields of South Wales; there is, however, a marked thinning out in the thickness of the Carboniferous rock in the Forest of Dean as compared with the development of those rocks in South Wales and Bristol. At Clifton, near Bristol, the total thickness of the Carboniferous Limestone is about 2900 feet, at the northern end of the Forest of Dean Coal-field it is about 600 feet.

In a paper read before the Birmingham Philosophical Society in 1882, it was announced by Professor Lapworth that the discovery of fossils in some shales underlying the productive Coalmeasures of Warwickshire, and coloured on the Geological Survey Map as Coal-measures, proved that these shales must be of Cambrian age (Lower Silurian of the Geological Survey). As the true age of these shales had for many years been a debateable question, Professor Lapworth's discovery was of considerable interest, and has led to an important alteration being made in the map, the supposed Lower Coal-measures and Millstone Grit having both been now relegated to the Lower Silurian (Lingula Flags). It may be of interest, before entering on the description of these beds, to trace shortly the history of the error in their classification.

These rocks may be classed into five or six more or less distinct groups.

I. Syenitic Rocks (Croft Series).

II. Andesite and Andesitic Tuffs (Caldecote Series).

III. Hartshill Quartzite with Breccia at its base.

IV. Diorites.

V. Andesites or Diorites containing Augite.

VI. Basalts or Diorites containing Olivine.

The three last groups appear to graduate into one another, and seem to correspond with similar rocks described by Mr. Allport. Many of the specimens examined are in a more or less advanced stage of decomposition, calcite, serpentine, pyrites, etc., being very commonly present.

Locality.—West end of the Midland Railway cutting, between Nuneaton and Stockingford.

Several fragmentary specimens of this Trilobite, differing in size, yet exhibiting similar characters, have been collected from this locality. The most perfect, although one of the smallest, is best fitted for description.

The best reply that I can make to Prof. Hughes’ remarks, in the Geological Magazine for November, on the Ffynnon Beuno Caves, is to publish the substance of the report presented to the British Association, especially as an opportunity will be given to those interested in the inquiry to examine the section during the further explorations to be carried on, probably in the month of June next year. Some of his statements—especially as regards the position of the fence, which is entirely at the opposite end of the cavern to that at which the flint flake was found, also as to the position of the flake, and. the nature of the deposits overlying it—are so entirely misleading, that I can only account for such statements being made by the fact that Prof. Hughes did not visit the section, though strongly urged by me to do so, until it had been almost entirely covered over, and work for the time suspended, and by his hasty survey of the surrounding conditions.

Geol. Mag. November Number, p. 492, line 10, delete “difficult.”