^{page 486 note 1} Not fractures exclusively (see Quart. Journ., p. 251, 1862, by the author). The author thinks these flexures are in consequence of uneven upheaval, often in binomial curves, along and at right angles to a curved axis, elevated most in the Pluvial Period at Crowboro’, and before denudation commenced; flexures, longitudinal and transverse, aided by side streams, principally guide the Wealden watercourses and rivers in their remarkable course; this I shall prove by measured sections hereafter. (See Figs. 5 and 6.) —A. T., Nov. 1868.

^{page 486 note 2} Flexures in binomial curves may be seen in all Geological books, although they are not described as such by those who have drawn them.

^{page 487 note 1} Denudation is work done to produce stability in strata to bear their load under the new physical conditions established.

^{page 487 note 2} The author has a very interesting case of a river piercing a rock near Istrad Vellte, South Wales, which he will shortly describe, showing an actual case of denudation.

^{page 487 note 3} See, “Remarks on Denudation,” by the Author, read May, 1868, p. 71, vol. xxv., Quart. Journ. All tributaries adjust their bottom levels in relation to the main stream. They cannot cut down their beds when the main stream blocks their water.

^{page 487 note 4} Humphreys and Abbot, page 414.

^{page 487 note 5} See Sir H. Davy.

^{page 489 note 1} Report on the Mississippi. U.S. War Department, 1864, p. 434.

^{page 489 note 2} Op. cit., p. 93.

^{page 489 note 3} Page 113, Humphreys and Abbot, 1864.

^{page 491 note 1} See p. 63, Quart. Journ., 1869.

^{page 491 note 2} The probability of the Mississippi Delta being partly marine was suggested by A. T., p. 272, Phil. Mag., 1853:—“If the further examination of the Delta of the Mississippi shows marine or fluvio-marine strata,” etc.

^{page 491 note 3} Gnathodon cuneatus, a common brackish-water bivalve.

^{page 493 note 1} M. Belgrand has, since the date on which this paper was written, 1868, confirmed this view in his great work on the Seine.

^{page 494 note 1} The author suggested the Delta being marine in the Phil. Mag. p. 272, and also the probability of the rainfall and denudation being many times greater than at present. Phil. Mag. 1853.

^{page 494 note 2} Mr. T. Login, Quart. Journ., vol. xxviii., has added some valuable information as to the Ganges deposits.

^{page 495 note 1} According to the accounts of early travellers.