In a paper on “The Physical Conditions under which the Cambrian and Lower Silurian Rocks were probably deposited over the European Area,” Mr. Hicks has recently put forth some opinions on the lowest fossiliferous rocks of Scandinavia and Russia, and their relations, as to age and stratigraphical characters, to those of Britain, which I think ought to be somewhat modified. The chief assertions in Mr. Hicks's paper are, that at the Pre-Cambrian period a large continent existed in Europe; that a subsidence began in the south-western part, and gradually extended to the north-eastern, which was not submerged until the Tremadoc group had been deposited over the western areas; and, finally, that the marine faunas migrated from the south-west. In order to prove these generalizations, Mr. Hicks makes a comparison between the most important Cambrian districts of Europe. He thinks that the British Cambrian rocks are the oldest, that the lowest Swedish beds are probably equivalent to the British Menevian group, and that the Russian are not older than the Arenig. Though the scantiness of the organic remains in some instances makes it very difficult, or, indeed, impossible to parallelize with certainty the oldest deposits of the various countries, it seems, however, from the palæontological facts already known, quite unquestionable that the lowest rocks of Scandinavia and Russia are older than Mr. Hicks has supposed them to be in comparison to those of Britain.