page 169 note * See my papers in the ‘Nautical Magazine’ of November and December, 1862 (a corrected copy of which appeared in the ‘Daily News’ of December 24, 1862); also my “Reply to Dr. Wallich's Statements,” Naut. Mag., March, 1863.

page 170 note * Quarterly Journal of the Geological Society, vol. vi. p. 86. I formed the opinion before learning that Mr. Godwin-Austen had advanced a similar one.

page 172 note * I noticed these terraces at the Dublin meeting of the British Association, in 1857, in connection with the remarkable jointing associated with them. An abstract of a paper, which contained a further notice of this jointing, ia given in the British Association Report of 1857. Professor Jukes has also noticed the terraces and jointing of the Clare Hills in his ‘Manual of Geology,’ 2nd edit., 1862.

page 173 note * Journ. Geol. Soc. vol. xi. p. 110.

page 176 note * The flat country lying between Dublin and Galway would, under the conditions named in the text, form an upland plain. From all I can observe, the district around Galway has been covered with subaerial drift (formed during the first glacial epoch) of not less than 300 feet in thickness; I find patches of it lying at a height equal to the number of feet mentioned at Tonabrocken. Much of this drift, in my opinion, has been considerably worn down completely or swept away, at the close of the first and in the middle of the second subaerial epochs. On the worn-down undulating surfaces of this old drift, erratic blocks of granitic rocks, etc., are common: these, I consider, have been transported by, and dropped from, icebergs during the subaqueous epoch of the glacial period. Much information on the subject of Irish drifts and erratics is given by Dr. Noyer in his highly interesting paper, published in the ‘Geologist’ of last July. Notwithstanding its original great thickness, the singular fact is common around Galway, that in no case where the limestone has been denuded of the subaerial drift do the wide cracks and joints prevalent in the rock contain a particle of it: one would have imagined the very contrary. I can only account for its absence on the view, advanced in the text, that the limestone, on which the drift was originally deposited, has, in addition to the degradation which it underwent towards the close of the first (subaerial) epoch, been much abraded by the winter glaciation of the third (subaerial) one; thereby exposing beds which were not uppermost when the drift was in course of deposition.

^{page 176 note †} Apparently Mr. Prestwich does not go so far in the views stated as I do. All the evidences bearing on the physico-geographical changes noticed in the text show that the intervening time, between the epochs to which the two series of flint-implement gravels are referred, was of enormous length. The Rev. Mr. Symonds correctly observes that the physical geology of the oldest or highest of the Somme valley gravels “proves their immense antiquity even more than do their fossil remains.” (Geology of the Railway, p. 14.)

page 177 note * Mem. Geol. Survey, vol. i. p. 348.