In submitting the following paper to the readers of the GEOLOGICAL MAGAZINE, I am conscious that some apology is needed for entering upon so difficult a subject. My position is as follows:—In 1879 the late Mr. E. B. Tawney joined me in the investigation of a series of detached blocks trawled from time to time by the Brixham fishermen. The character of certain of these stones having suggested to Mr. Tawney the idea that the schists of South Devon might possibly be of pre-Cambrian age, he visited the district in 1880, with the expectation of being the first to advance that hypothesis. The evidence of the schists themselves failed to satisfy Mr. Tawney on the point in question, and his premature death prevented his attacking the problem on a subsequent occasion, as he had hoped to be able to do.

In the course of a visit to the Hunsruck district between Treves and Bingen in the spring of 1890, in company with Professor Gosselet, Mons. C. Barrois, Herr von Eeinach and Herr Grebe, I was struck by the resemblance displayed by the Permian quartz porphyry of the valley of the Nahe, between Birkenfeld and Bingen, to fragments contained in the breccias of Teignmouth. In discussing the South Devon section with the two gentlemen last named, on that occasion, they both gave it as their opinion that the lower beds of the Devon section might prove to be representatives of the Bothliegende.

In recent papers which I have printed in the GEOLOGICAL MAGAZINE I have tried to show that some of the greatest mountain chains in the world are of very recent origin; and that this accounts for their showing no traces, or very slight ones, of the action of ice on a wide-spread scale.

I have, in fact, ventured to lay down the conclusion that the presence or absence of such traces of ice-action is a test of whether these mountains existed at the so-called Glacial period or not.

In the Geological Magazine (Dec. III. Vol. VIII. No. 329, p. 493, Nov. 1891), Mr. E. T. Newton has a “Note on the Occurrence of Am. jurensis in the Ironstone of the Northampton Sands in the Neighbourhood of Northampton.” This note had especial interest for me, from my having contested Mr. Beeby Thompson's view of the Jurensis-zone being represented by the clayey beds beneath the Sands; and, in fact, it seemed to support my argument. Further reading, however, obliged me to confess that I could not claim this support; for Mr. Newton says (p. 494), “that the specimens of Am. jurensis agree exactly with Dr. Wright's plate 79 (Lias Ammonites).”

In “The Cause of an Ice Age” Sir R. Ball claims to have removed from the Astronomical Theory of Glaciation the greatest stumbling block in the way of its general acceptance, and to have placed it on a firm and unassailable foundation. And this stumbling block he considers to have been Sir J. Herschel's erroneous statement, that, of the total heat received by a hemisphere in a year, one-half is received during the summer, and the other half dining winter.