335-APrinciples of Geol., p. 696.335-BFor changes in climate, see Principles of Geol., chaps. vii. and viii.335-CGeol. Trans., 2d series, vol. vi. p. 330.336-AAgassiz, Poiss. Foss., lib. 4. p. 62. and liv. 5. p. 88.337-AGoldfuss, Neue Jenaische Lit. Zeit., 1848; and Von Meyer, Quart. Geol. Journ., vol. iv. p. 51., memoirs.338-ASee Lyell's Second Visit, &c., vol. ii. p. 305.340-AThese impressions, found by Mr. Lea, were imagined to be in a rock as ancient as the old red sandstone; but, according to Mr. H. D. Rogers, they are in the lowest part of the coal formation.341-APhillips, Geol. of Yorksh., vol. ii. p. 208.342-APhillips, Geol. of Yorksh., pl. 20. fig. 65.342-BIbid., pl. 17. fig. 15.342-CSee section,fig. 318.p. 287.343-AThe Old Red Sandstone, by Hugh Miller, 1841.345-AOld Red Sandstone. Plate 1. fig. 1. Mr. M.'s description of the fish is most graphic and correct.347-ACamb. Phil. Trans., vol. vi. pl. 8. fig. 2.349-ASee Proceedings of Geol. Soc., and the anniversary speech of Dr. Buckland, P. G. S., for 1841.349-BLyell's Second Visit to the United States, vol. ii. p. 277.350-AMemoir on the Hartz, Palæontographica of Dunker and Von Meyer, part iii.352-AMurchison, Silurian System, p. 198, 199.354-ASilurian System, pl. 7. bis. fig. 1. b.358-AQuart. Geol. Journ., vol. ii. p. 11.; and Memoirs of Geol. Survey, vol. ii. p. 518.359-AQuart. Geol. Journ., vol. iv. p. 300.359-BIbid., 299.359-CIbid., 145.360-ASince this was written, Mr. Logan has discovered chelonian footprints in the lowest fossiliferous beds of the Silurian series, near Montreal, in Canada. Professor Owen inclines to refer them to the genusEmys.—Quart. Journ. G. S., vol. vii. p. lxxvi.368-AFor a description and theory of active volcanos, see Principles of Geology, chaps. xxiv. to xxvii.374-AG. Rose, Ann. des Mines, tom. viii. p. 32.374-BGeol. Trans. vol. ii. p. 211. 2d series.378-AI have been favoured with this drawing by Captain B. Hall.381-ACambridge Transactions, vol. i. p. 402.382-ACambridge Trans., vol. i. p. 410.382-BIbid. vol. ii. p. 175.382-CDr. Berger, Geol. Trans., 1st series, vol. iii. p. 172.382-DGeol. Trans., 1st series, vol. iii. p. 210. and plate 10.382-EIbid. p. 201.383-AGeol. Trans., 1st series, vol. iii. p. 205.383-BIbid. p. 213.; and Playfair, Illust. of Hutt. Theory, p. 253.383-CGeol. Trans., 1st series, vol. iii. p. 206.383-DSedgwick, Camb. Trans. vol. ii. p. 37.383-EIllust. of Hutt. Theory, § 253. and 261. Dr. MacCulloch, Geol. Trans., 1st series, vol. ii. p. 305.383-FSyst. of Geol. vol. i. p. 206.384-ACamb. Trans. vol. ii. p. 180.385-AMacCul. Syst. of Geol. vol. ii. p. 137.385-BSeale's Geognosy of St. Helena, plate 9.386-AFortis. Mém. sur l'Hist. Nat. de l'Italie, tom. i. p. 233. plate 7.387-AScrope, Geol. Trans. vol. ii. p. 205. 2d series.389-ASee Princ. of Geol.,Index, "Graham Island," "Nyöe," "Conglomerates, volcanic," &c.390-AMacCulloch, West. Isl., vol. ii. p. 487.390-BSyst. of Geol., vol. ii. p. 114.390-CIbid.392-ASee Principles, chaps. xxiv-xxvii.393-ASee Principles, chaps. xxvi. and xxx.; 8th ed. p. 397-475.394-ASee Principles of Geol. ch. xxiv. (8th ed. p. 355.).394-BSee Lyell on Craters of Denudation, Quart. Geol. Journ. vol. vi. p. 232.399-ACaldcleugh, Phil. Trans. 1836. p. 27., and Official Documents of Nicaragua.399-BSee Principles,Index, "Skaptar Jokul."401-AThis view of the Isle of Cyclops is from an original drawing by my friend the late Captain Basil Hall, R. N.404-AConsult the valuable memoir of M. L. A. Necker, Mém. de la Soc. de Phys. et d'Hist. Nat. de Génève, tom. ii. part i. Nov. 1822.405-AFrom a drawing of M. Necker, in Mém. above cited.405-BPhil. Trans., vol. lxx., 1780.409-AMaclure, Journ. de Phys., vol. lxvi. p. 219., 1808; cited by Daubeny, Description of Volcanos, p. 24.410-AThis view is taken from a sketch which I made on the spot in 1830.416-ATrans. of Geol. Soc., 2d series, vol. v.419-AScrope, Edin. Journ. of Sci., June, 1826, p. 145.419-BHibbert, Extinct Volcanos of the Rhine, p. 24.422-ASee the map,p. 179.423-AScrope's Central France, p. 98.423-BSee chaps. xxiv., xxv., and xxvi., 7th and 8th editions.423-CSee Quarterly Geol. Journ., vol. ii. p. 77.425-AFor a view of Puy de Tartaret and Mont Dor, see Scrope's Volcanos of Central France.427-AScrope's Central France, p. 60., and plate.428-ADaubeny on Volcanos, p. 14.428-BEdin. Journ. of Sci., No. iv. N. S. p. 276. Figures of some of these remains are given by M. Bertrand de Doue, Ann. De la Soc. d'Agricult. de Puy, 1828.429-AMém. de la Soc. Géol. de France, tom. i. p. 175.429-BSee Lyell and Murchison, Ann. de Sci. Nat., Oct. 1829.430-ASee Scrope's Central France, p. 21.430-BIbid, p. 7.431-ABoblaye and Virlet, Morea, p. 23.432-ADe la Beche, Geol. Proceedings, No. 41. p. 196.432-B"The rock," as English readers of Burn's poems may remember, is a Scotch term for distaff.435-AMurchison, Silurian System, &c. p. 230.435-BIbid., p. 272.435-CIbid., p. 325.435-DChap. XXVII.p. 356.435-EGeol. Trans., 2d series, vol. iv. p. 55.439-ABulletin, 2d sèrie, iv. 1304.; and Archiac, Hist. des Progrès de Geol., i. 38.440-ABoase on Primary Geology, p. 16.441-ABulletin, vol. iv., 2d ser., pp. 1318. and 1320.441-BSyst. of Geol., vol. i. p. 157.441-CIbid., p. 158.442-AGeol. Trans., 1st series, vol. iii. pl. 21.442-BMacCulloch, Geol. Trans., vol. iii. p. 259.443-ACapt. B. Hall, Trans. Roy. Soc. Edin., vol. vii.444-AMacCulloch, Syst. of Geol., vol. i. p. 58.444-BWestern Islands, pl. 31.444-COn Geol. of Cornwall, Camb. Trans. vol. i. p. 124.445-APhil. Mag. and Annals, No. 27. new series, March, 1829.445-BNecker, sur la Val. de Valorsine, Mém. de la Soc. de Phys. de Génève, 1828. I visited, in 1832, the spot referred to in fig. 497.446-ANecker, Proceedings of Geol. Soc., No. 26. p. 392.446-BSee Keilhau's Gæa Norvegica; Christiania, 1838.450-ASilliman's Journ., No. 69. p. 123.450-BSee "Principles,"Index, "Jorullo."451-A"Principles,"Index, "Volcanic Eruptions."453-ADarwin, pp. 390. 406.; second edition, p. 319.454-ASee map of Europe and explanation, in Principles, book i.456-AElie de Beaumont, sur les Montagnes de l'Oisans, &c. Mém. de la Soc. d'Hist. Nat. de Paris, tom. v.456-BSee Murchison, Geol. Trans., 2d series, vol. ii. part ii. pp. 311-321.456-CWestern Islands, vol. i. p. 330. plate 18., figs. 3, 4.456-DVon Buch, Annales de Chimie, &c.457-AProceedings of Geol. Soc., vol. ii. p. 562.457-BSee the Gæa Norvegica and other works of Keilhau, with whom I examined this country.459-AMurchison, Geol. Trans., 2d series, vol. ii. p. 307.459-BGeognostische Wanderungen, Leipzig, 1838.461-AIn the above section I have attempted to represent the new discoveries made since 1839, by Mr. Necker and Mr. A. C. Ramsay, in regard to the plutonic formations, 6.a, and 6.b.463-AFor the geology of Arran consult the works of Drs. Hutton and MacCulloch, the Memoirs of Messrs. Von Dechen and Oeynhausen, that of Professor Sedgwick and Sir R. Murchison (Geol. Trans. 2d series), Mr. L. A. Necker's Memoir, read to the Royal Soc. of Edin. 20th April, 1840, and Mr. Ramsay's Geol. of Arran, 1841. I examined myself a large part of Arran in 1836.469-AGeol. Trans., 2d series, vol. iii. p. 480.469-BThe Silurian System of Rocks, as developed in Salop, Hereford, &c., p. 245.469-CIbid., p. 246.470-AIntroduction to Geology, chap. iv.471-ASilurian System of Rocks, &c., p. 246.471-BReport, Brit. Ass., Cork, 1843, p. 60.471-CQuart. Geol. Journ., vol. iii. p. 87. 1847.472-AGeol. Obs. on S. America, 1846, p. 168.472-BMargaric acid is an oleaginous acid, formed from different animal and vegetable fatty substances. A margarate is a compound of this acid with soda, potash, or some other base, and is so named from its pearly lustre.472-CLetter to the author, dated Cape of Good Hope, Feb. 20. 1836.474-AKeilhau, Gæa Norvegica, pp. 61-63.475-AGeol. Manual, p. 479.475-BPhil. Trans., 1804.476-APoggendorf's Annalen, No. xvi., 2d series, vol. iii.476-BSee Principles,Index, "Carbonated Springs," &c.476-CHoffmann's Liparischen Inseln, p. 38. Leipzig, 1832.477-ASee Princ. of Geol.; and Bulletin de la Soc. Géol. de France, tom. ii. p. 230.477-BSee Princ. of Geol.; and Daubeny's Volcanos, p. 167.477-CJam. Ed. New Phil. Journ., No. 51. p. 43.478-ASyst. of Geol., vol. i. p. 210.478-BIbid., p. 211.478-CSee above, pp. 327, 333.479-ASee Lyell, Quart. Geol. Journ., vol. i. p. 199.479-BDr. Boase, Primary Geology, p. 319.480-AGeol. Trans., 2d series, vol. ii. p. 227.480-BDarwin, Volcanic Islands, pp. 69, 70.480-CGeol. Obs. in S. America, p. 167. See also above, p. 471.480-DBulletin, vol. iv. p. 1301.483-ASee notices of Savi, Hoffmann, and others, referred to by Boué, Bull. de la Soc. Géol. de France, tom. v. p. 317.; and tom. iii. p. xliv.; also Pilla, cited by Murchison, Quart. Geol. Journ., vol. v. p. 266.487-ASee Principles,Index, "Calcareous Springs."489-APrinciples, &c. chap. iv. 8th ed. p. 49.491-AGeol. Trans. vol. iv. p. 139.; Trans. Roy. Geol. Society Cornwall, vol. ii. p. 90.492-ACarne, Trans. of Geol. Soc. Cornwall, vol. iii. p. 238.492-BFournet, Etudes sur les Dépots Metalliferes.493-AGeol. Rep. on Cornwall, p. 340.493-BPrinciples, ch. xxvii. 8th ed. p. 422.496-ASee Dr. Daubeny's Volcanos.496-BBulletin, iv. p. 1278.497-AR. W. Fox on Mineral Veins, p. 10.497-BIbid. p. 38.498-AI am indebted to Sir H. De la Beche for this information. See also maps and sections of Irish Survey.498-BSir H. De la Beche, MS. notes on Irish Survey.499-AReport on Geology of Cornwall, p. 310.501-ASee Principles of Geol., Book 3.501-BSee the author's Anniv. Address to the Geol. Soc. 1837. Proceedings of G. S. No. 49. p. 520.
335-APrinciples of Geol., p. 696.
335-BFor changes in climate, see Principles of Geol., chaps. vii. and viii.
335-CGeol. Trans., 2d series, vol. vi. p. 330.
336-AAgassiz, Poiss. Foss., lib. 4. p. 62. and liv. 5. p. 88.
337-AGoldfuss, Neue Jenaische Lit. Zeit., 1848; and Von Meyer, Quart. Geol. Journ., vol. iv. p. 51., memoirs.
338-ASee Lyell's Second Visit, &c., vol. ii. p. 305.
340-AThese impressions, found by Mr. Lea, were imagined to be in a rock as ancient as the old red sandstone; but, according to Mr. H. D. Rogers, they are in the lowest part of the coal formation.
341-APhillips, Geol. of Yorksh., vol. ii. p. 208.
342-APhillips, Geol. of Yorksh., pl. 20. fig. 65.
342-BIbid., pl. 17. fig. 15.
342-CSee section,fig. 318.p. 287.
343-AThe Old Red Sandstone, by Hugh Miller, 1841.
345-AOld Red Sandstone. Plate 1. fig. 1. Mr. M.'s description of the fish is most graphic and correct.
347-ACamb. Phil. Trans., vol. vi. pl. 8. fig. 2.
349-ASee Proceedings of Geol. Soc., and the anniversary speech of Dr. Buckland, P. G. S., for 1841.
349-BLyell's Second Visit to the United States, vol. ii. p. 277.
350-AMemoir on the Hartz, Palæontographica of Dunker and Von Meyer, part iii.
352-AMurchison, Silurian System, p. 198, 199.
354-ASilurian System, pl. 7. bis. fig. 1. b.
358-AQuart. Geol. Journ., vol. ii. p. 11.; and Memoirs of Geol. Survey, vol. ii. p. 518.
359-AQuart. Geol. Journ., vol. iv. p. 300.
359-BIbid., 299.
359-CIbid., 145.
360-ASince this was written, Mr. Logan has discovered chelonian footprints in the lowest fossiliferous beds of the Silurian series, near Montreal, in Canada. Professor Owen inclines to refer them to the genusEmys.—Quart. Journ. G. S., vol. vii. p. lxxvi.
368-AFor a description and theory of active volcanos, see Principles of Geology, chaps. xxiv. to xxvii.
374-AG. Rose, Ann. des Mines, tom. viii. p. 32.
374-BGeol. Trans. vol. ii. p. 211. 2d series.
378-AI have been favoured with this drawing by Captain B. Hall.
381-ACambridge Transactions, vol. i. p. 402.
382-ACambridge Trans., vol. i. p. 410.
382-BIbid. vol. ii. p. 175.
382-CDr. Berger, Geol. Trans., 1st series, vol. iii. p. 172.
382-DGeol. Trans., 1st series, vol. iii. p. 210. and plate 10.
382-EIbid. p. 201.
383-AGeol. Trans., 1st series, vol. iii. p. 205.
383-BIbid. p. 213.; and Playfair, Illust. of Hutt. Theory, p. 253.
383-CGeol. Trans., 1st series, vol. iii. p. 206.
383-DSedgwick, Camb. Trans. vol. ii. p. 37.
383-EIllust. of Hutt. Theory, § 253. and 261. Dr. MacCulloch, Geol. Trans., 1st series, vol. ii. p. 305.
383-FSyst. of Geol. vol. i. p. 206.
384-ACamb. Trans. vol. ii. p. 180.
385-AMacCul. Syst. of Geol. vol. ii. p. 137.
385-BSeale's Geognosy of St. Helena, plate 9.
386-AFortis. Mém. sur l'Hist. Nat. de l'Italie, tom. i. p. 233. plate 7.
387-AScrope, Geol. Trans. vol. ii. p. 205. 2d series.
389-ASee Princ. of Geol.,Index, "Graham Island," "Nyöe," "Conglomerates, volcanic," &c.
390-AMacCulloch, West. Isl., vol. ii. p. 487.
390-BSyst. of Geol., vol. ii. p. 114.
390-CIbid.
392-ASee Principles, chaps. xxiv-xxvii.
393-ASee Principles, chaps. xxvi. and xxx.; 8th ed. p. 397-475.
394-ASee Principles of Geol. ch. xxiv. (8th ed. p. 355.).
394-BSee Lyell on Craters of Denudation, Quart. Geol. Journ. vol. vi. p. 232.
399-ACaldcleugh, Phil. Trans. 1836. p. 27., and Official Documents of Nicaragua.
399-BSee Principles,Index, "Skaptar Jokul."
401-AThis view of the Isle of Cyclops is from an original drawing by my friend the late Captain Basil Hall, R. N.
404-AConsult the valuable memoir of M. L. A. Necker, Mém. de la Soc. de Phys. et d'Hist. Nat. de Génève, tom. ii. part i. Nov. 1822.
405-AFrom a drawing of M. Necker, in Mém. above cited.
405-BPhil. Trans., vol. lxx., 1780.
409-AMaclure, Journ. de Phys., vol. lxvi. p. 219., 1808; cited by Daubeny, Description of Volcanos, p. 24.
410-AThis view is taken from a sketch which I made on the spot in 1830.
416-ATrans. of Geol. Soc., 2d series, vol. v.
419-AScrope, Edin. Journ. of Sci., June, 1826, p. 145.
419-BHibbert, Extinct Volcanos of the Rhine, p. 24.
422-ASee the map,p. 179.
423-AScrope's Central France, p. 98.
423-BSee chaps. xxiv., xxv., and xxvi., 7th and 8th editions.
423-CSee Quarterly Geol. Journ., vol. ii. p. 77.
425-AFor a view of Puy de Tartaret and Mont Dor, see Scrope's Volcanos of Central France.
427-AScrope's Central France, p. 60., and plate.
428-ADaubeny on Volcanos, p. 14.
428-BEdin. Journ. of Sci., No. iv. N. S. p. 276. Figures of some of these remains are given by M. Bertrand de Doue, Ann. De la Soc. d'Agricult. de Puy, 1828.
429-AMém. de la Soc. Géol. de France, tom. i. p. 175.
429-BSee Lyell and Murchison, Ann. de Sci. Nat., Oct. 1829.
430-ASee Scrope's Central France, p. 21.
430-BIbid, p. 7.
431-ABoblaye and Virlet, Morea, p. 23.
432-ADe la Beche, Geol. Proceedings, No. 41. p. 196.
432-B"The rock," as English readers of Burn's poems may remember, is a Scotch term for distaff.
435-AMurchison, Silurian System, &c. p. 230.
435-BIbid., p. 272.
435-CIbid., p. 325.
435-DChap. XXVII.p. 356.
435-EGeol. Trans., 2d series, vol. iv. p. 55.
439-ABulletin, 2d sèrie, iv. 1304.; and Archiac, Hist. des Progrès de Geol., i. 38.
440-ABoase on Primary Geology, p. 16.
441-ABulletin, vol. iv., 2d ser., pp. 1318. and 1320.
441-BSyst. of Geol., vol. i. p. 157.
441-CIbid., p. 158.
442-AGeol. Trans., 1st series, vol. iii. pl. 21.
442-BMacCulloch, Geol. Trans., vol. iii. p. 259.
443-ACapt. B. Hall, Trans. Roy. Soc. Edin., vol. vii.
444-AMacCulloch, Syst. of Geol., vol. i. p. 58.
444-BWestern Islands, pl. 31.
444-COn Geol. of Cornwall, Camb. Trans. vol. i. p. 124.
445-APhil. Mag. and Annals, No. 27. new series, March, 1829.
445-BNecker, sur la Val. de Valorsine, Mém. de la Soc. de Phys. de Génève, 1828. I visited, in 1832, the spot referred to in fig. 497.
446-ANecker, Proceedings of Geol. Soc., No. 26. p. 392.
446-BSee Keilhau's Gæa Norvegica; Christiania, 1838.
450-ASilliman's Journ., No. 69. p. 123.
450-BSee "Principles,"Index, "Jorullo."
451-A"Principles,"Index, "Volcanic Eruptions."
453-ADarwin, pp. 390. 406.; second edition, p. 319.
454-ASee map of Europe and explanation, in Principles, book i.
456-AElie de Beaumont, sur les Montagnes de l'Oisans, &c. Mém. de la Soc. d'Hist. Nat. de Paris, tom. v.
456-BSee Murchison, Geol. Trans., 2d series, vol. ii. part ii. pp. 311-321.
456-CWestern Islands, vol. i. p. 330. plate 18., figs. 3, 4.
456-DVon Buch, Annales de Chimie, &c.
457-AProceedings of Geol. Soc., vol. ii. p. 562.
457-BSee the Gæa Norvegica and other works of Keilhau, with whom I examined this country.
459-AMurchison, Geol. Trans., 2d series, vol. ii. p. 307.
459-BGeognostische Wanderungen, Leipzig, 1838.
461-AIn the above section I have attempted to represent the new discoveries made since 1839, by Mr. Necker and Mr. A. C. Ramsay, in regard to the plutonic formations, 6.a, and 6.b.
463-AFor the geology of Arran consult the works of Drs. Hutton and MacCulloch, the Memoirs of Messrs. Von Dechen and Oeynhausen, that of Professor Sedgwick and Sir R. Murchison (Geol. Trans. 2d series), Mr. L. A. Necker's Memoir, read to the Royal Soc. of Edin. 20th April, 1840, and Mr. Ramsay's Geol. of Arran, 1841. I examined myself a large part of Arran in 1836.
469-AGeol. Trans., 2d series, vol. iii. p. 480.
469-BThe Silurian System of Rocks, as developed in Salop, Hereford, &c., p. 245.
469-CIbid., p. 246.
470-AIntroduction to Geology, chap. iv.
471-ASilurian System of Rocks, &c., p. 246.
471-BReport, Brit. Ass., Cork, 1843, p. 60.
471-CQuart. Geol. Journ., vol. iii. p. 87. 1847.
472-AGeol. Obs. on S. America, 1846, p. 168.
472-BMargaric acid is an oleaginous acid, formed from different animal and vegetable fatty substances. A margarate is a compound of this acid with soda, potash, or some other base, and is so named from its pearly lustre.
472-CLetter to the author, dated Cape of Good Hope, Feb. 20. 1836.
474-AKeilhau, Gæa Norvegica, pp. 61-63.
475-AGeol. Manual, p. 479.
475-BPhil. Trans., 1804.
476-APoggendorf's Annalen, No. xvi., 2d series, vol. iii.
476-BSee Principles,Index, "Carbonated Springs," &c.
476-CHoffmann's Liparischen Inseln, p. 38. Leipzig, 1832.
477-ASee Princ. of Geol.; and Bulletin de la Soc. Géol. de France, tom. ii. p. 230.
477-BSee Princ. of Geol.; and Daubeny's Volcanos, p. 167.
477-CJam. Ed. New Phil. Journ., No. 51. p. 43.
478-ASyst. of Geol., vol. i. p. 210.
478-BIbid., p. 211.
478-CSee above, pp. 327, 333.
479-ASee Lyell, Quart. Geol. Journ., vol. i. p. 199.
479-BDr. Boase, Primary Geology, p. 319.
480-AGeol. Trans., 2d series, vol. ii. p. 227.
480-BDarwin, Volcanic Islands, pp. 69, 70.
480-CGeol. Obs. in S. America, p. 167. See also above, p. 471.
480-DBulletin, vol. iv. p. 1301.
483-ASee notices of Savi, Hoffmann, and others, referred to by Boué, Bull. de la Soc. Géol. de France, tom. v. p. 317.; and tom. iii. p. xliv.; also Pilla, cited by Murchison, Quart. Geol. Journ., vol. v. p. 266.
487-ASee Principles,Index, "Calcareous Springs."
489-APrinciples, &c. chap. iv. 8th ed. p. 49.
491-AGeol. Trans. vol. iv. p. 139.; Trans. Roy. Geol. Society Cornwall, vol. ii. p. 90.
492-ACarne, Trans. of Geol. Soc. Cornwall, vol. iii. p. 238.
492-BFournet, Etudes sur les Dépots Metalliferes.
493-AGeol. Rep. on Cornwall, p. 340.
493-BPrinciples, ch. xxvii. 8th ed. p. 422.
496-ASee Dr. Daubeny's Volcanos.
496-BBulletin, iv. p. 1278.
497-AR. W. Fox on Mineral Veins, p. 10.
497-BIbid. p. 38.
498-AI am indebted to Sir H. De la Beche for this information. See also maps and sections of Irish Survey.
498-BSir H. De la Beche, MS. notes on Irish Survey.
499-AReport on Geology of Cornwall, p. 310.
501-ASee Principles of Geol., Book 3.
501-BSee the author's Anniv. Address to the Geol. Soc. 1837. Proceedings of G. S. No. 49. p. 520.