The petrography of the Plateau Deposits has been determined. They yield species both of local origin and of the general Haldon types.

The kyanite and staurolite present have been derived from the north.

The planation of the limestones was initiated during the Cretaceous period.

The raised beaches are of slightly different types, the Thatcher raised beach being later. They furnish evidence of a former greater thickness of the Plateau Deposits.

Modern beach deposits furnish some evidence of the distributive powers of certain minerals, and point to the existence of Triassic and Cretaceous sediments outside the Bay.

The Upper Silurian rocks of Lesmahago, Lanarkshire, have long been known to contain Arthropod remains. In the Kelvin-grove Museum, Glasgow, are a number of curious forms from the Logan Water Lesmahago, which Professor McNair was good enough to allow me to examine. In the hope of solving some problems presented by them, I obtained, through the kindness of the Keeper of the Geological Department of the British Museum, the loan of a specimen from the same locality, which forms the subject of this note. Instead, however, of solving any difficulties, the specimen presented a new problem.

In recent years Professor J. W. Gregory has challenged, one after the other, our most cherished beliefs and creeds in the field of glacial geology, fearlessly raising again the discarded standards, dust-laden these many years; the gaping fissures of the fjords, the glacial submergence, the residual character of many moraines, eskers, and kames, including the beautiful York moraines, and now —the post-glacial origin of drumlins.

This important earthquake is chiefly of interest on account of its connexion with the strong Hereford earthquakes of 6th October, 1863, 30th October, 1868, and 17th December, 1896. At least three of the four earthquakes (those of 1863, 1896, and 1926) seem to have originated in the same twin-foci, the epicentre of one lying near Hereford and that of the other near Ross. The fourth earthquake (that of 1868) originated in the Ross focus, possibly also in the Hereford focus.

(a) The insoluble residues from the limestones contain detrital quartz, amorphous, cryptocrystalline and microcrystalline silica, siliceous pseudomorphs after organic remains, sponge spicules, fluor, magnetite, pyrites, zircon, ilmenite, tourmaline, muscovite, biotite, and felspar.

(b) No megascopic chert occurs.

(c) The succession contains more arenaceous and argillaceous rocks than occur in the Avon section. They contain magnetite, rutile, zircon, ilmenite, tourmaline, muscovite, and staurolite among the rarer constituents

(d) Oolites have a notably small average percentage of insoluble residues, probably owing to their rapid formation, in clear water.

(e) The detrital material in the Avonian rocks of Sodbury has probably been derived, directly or indirectly, from some Pre-cambrian complex to the north or north-west.

Only a single crab (Carcineretes woolucotti Withers, Ann. May. Nat. Hist., ser. ix, vol. x, 1922, p. 535, pls. xvi, xvii; vol. xiii, 1924, p. 91, pl. iv, figs. 1–4) has so far been described from the Cretaceous rocks of Jamaica. Remains of this crab have been found in the upper part of the Rudist Limestone both at Logie Green and Trout Hall, near the Rio Minho River, Central Jamaica. Dr. C. T. Trechmann, F.G.S., has now discovered a second species of crab, Ranina trechmanni n. sp., and this was found in the shales some 40 feet below the Rudist Limestone between Cambridge and Catadupa, West Central Jamaica. The Rudist Limestone is considered by Dr. Trechmann (Geol. Mag., Vol. LIX, 1922, p. 505; Vol. LX, 1923, p. 345; Vol. LXI, 1924, p. 393) to be of Maestrichtian age, and the shales below, in which the present crab occurs, to be Campanian. This conclusion is borne out by, and to a great extent based on, the evidence of the Cephalopods described by Dr. L. F. Spath (Geol. Mag., Vol. LXII, 1924, p. 28) from the shales underlying the Rudist Limestone at Providence, Port Antonio, Eastern Jamaica, and considered by him to be of Upper Senonian and Maestrichtian age. Professor H. L. Hawkins, however, from a study of the Echinoids (Geol. Mag., Vol. LX, 1923, p. 215) does not agree that these rocks are so high in the Cretaceous as the Campanian or Maestrichtian, and considers that they have a time range from the base of the Upper Cretaceous to about the base of the Senonian.

Page 123, for Middle Louth Seam read Middle Lount Seam. The quartzite pebble described was exhibited at the Geological Society on 22nd April, 1925 (Proc. Geol. Soc., Q.J.G.S., lxxxi, 1925, p. cxxiv), and has since been presented to the Museum of Practical Geology, Jermyn Street.

Page 143, line 9 from bottom, for J. P. Paul read F. P. Paul.

Page 143, line 7 from bottom, for endialite read eudialite.

Page 143, line 7 from bottom, for Shannon Pier read Shannon Tier.