The transported blocks of the Indus Valley are not without some interest in connexion with the theory of an Indian Glacial Period akin to that of Europe, and with regard to the support they do or do not give to that supposition.

Shropshire was always considered by Sir Roderick Murchison as one of the districts in which his Upper Silurian rocks could be most advantageously studied.1 We propose, therefore, in this communication to offer some few notes on the Geology and Palæntology of the Wenlock and Ludlow series; illustrated by the Brachiopoda, reserving for the present what we may have to communicate with respect to the Upper Llandovery.

The above brief description of the Cortland rocks prepares the way for a consideration of their relation to the other rocks of the county. The following questions arise: Are they one with the latter in system ? are they rocks of an earlier system ? or are they eruptive rocks, and not metamorphic, and hence, of no bearing on the general question as to the age of the Westchester limestones and the associated schists ?

In England the Great Oolite of Minchinhampton contains the greater number of species belonging to this peculiar group of Haliotidœ. Morris and Lycett (Great Oolite Mollusca, p. 80) give a full and interesting diagnosis of the genus, which has oniy one representative in the Corallian beds of Yorkshire. D'Orbigny figures half a dozen species of Troehotoma from the Corallian of France, and Buvignier gives three from the Coral Rag of the Meuse. None are quoted by Be Loriol from the Séquanien of Boulogne.

In Mr. Geikie's admirable work on “Prehistoric Europe,” in the chapter “On British Post-Glacial and Recent Deposits,” he alludes more than once in very flattering terms to my share in elucidating Cornish Post-Tertiary Geology, at the same time, however, questioning certain conclusions attributed to me with reference to the general correlation of the Forest-beds in stream-sections, i.e. those resting on the tin ground, with the Forests “exposed upon the present foreshore.”

In the Report on the Geology of the Henry Mountains, Rocky Mountain Region, Mr. G. K. Gilbert, of the U.S. Geographical and Geological Survey, points out that many of the intrusions of eruptive rocks now exposed had a deep-seated origin; the molten rock having filled vacancies in the rocks, and never coming to the surface until they were exposed by denudation or by faults. To quote our author, “The lava … instead of rising through all the beds of the earth's crust, stopped at a lower horizon, insinuated itself between two strata, and opened for itself a chamber by lifting all the superior beds. For these masses of eruptive rocks, Gilbert proposes the name laccolite (Gr. lakkos cistern, and lithos stone). In the Cos. Wexford and Wioklow some of the protrusions of eruptive rocks are entitled to this name, the rocks having congealed in cisterns below the surface of the earth; there are, however, some marked differences between them and the laccolites of the Henry Mountains. The latter were intruded into nearly horizontal strata, the laccolites only consist of one kind of rock, while the adjoining rocks seem to have been very little altered. But the Wexford and Wicklow laccolites, on the other hand, were intruded into highly disturbed strata, they are made up of a variety of rocks, and always the aquo-igneous action due to their intrusion—‘ baked ’ or altered, a greater or less thickness of rocks about them.