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Published online by Cambridge University Press: 01 May 2009
The cause of changes in Climate during past Geological periods having lately become, and being likely to continue, a prominent topic of interest, I have attempted here to bring together the more prominent features in the controversy, under the idea that to many readers, who have not either the time or the inclination to more closely examine the subject, this may be acceptable. In so doing I have, with one partial exception, confined myself to discussing the difficulties which beset all the various theories offered as a solution, rather than attempted the advocacy of any one of those theories in particular.
page 386 note 1 Sir C. Lyell, in his “Principles,” states, however, that Sir John Herschel informed him, that although the limit calculated by Laplace (1° 21') was true as regards the last 100,000 years, yet if millions of years were taken into account, it was conceivable that the variation might be found to extend to three, or even four degrees.
page 388 note 1 It appears that this period of 10,500 years is subject to large variations; but it is convenient to speak of it as of that duration.
page 390 note 1 I am not aware on what observations these temperatures are based; but if they were taken at land stations exclusively, or preponderatingly, the fact alleged to result from them may not be free from question.
page 396 note 1 The insect remains from Lexden, one of the numerous Post-Glacial brick-earths of England, were considered by MrWollaston, to indicate a warmer climate than our present one.—Q. J. G. S. vol. xix. p. 399.Google Scholar
page 396 note 2 For the grounds of the views thus summarized see papers in the following, viz. Quart. Journ. of the Geol. Soc. vol. xxiii. p. 394, vol. xxiv. p. 146, vol. xxvi. p. 90, vol. xxvii. p. 3Google Scholar; Geol. Mag. Vol. VII. pp. 17 and 61, Vol. VIII. p. 406, Vol. IX. pp. 153, 171, and 352. I hope at a future time to explain in more detail the evidence indicative of the Post-Glacial submergence referred to in the text, which is that to which the Hessle Clay of the North-East, and the Upper Boulder-clay of the North-West of England are in my opinion due.Google Scholar
page 397 note 1 Report of the progress of the Hassler Expedition, in Nature for August 1, 1872.
page 398 note 1 Geol. Mag. 1876, Decade II. Vol. III. p. 266.Google Scholar
