(1) 'Siluria.' Sir Roderick Murchison. 5th ed., pp. 21-46. (2) 'Synopsis of the Classification of the British Palæozoic Rocks.' Sedgwick. Introduction to the 3d Fasciculus of the 'Descriptions of British Palæozoic Fossils in the Woodwardian Museum,' by F. M'Coy, pp. i-xcviii, 1855. (3) 'Catalogue of the Cambrian and Silurian Fossils in the Geological Museum of the University of Cambridge.' Salter. With a Preface by Prof. Sedgwick. 1873. (4) 'Thesaurus Siluricus.' Bigsby. 1868. (5) "History of the Names Cambrian and Silurian." Sterry Hunt.--'Geological Magazine.' 1873. (6) 'Système Silurien du Centre de la Bohême.' Barrande. Vol. I. (7) 'Report of Progress of the Geological Survey of Canada, from its Commencement to 1863,' pp. 87-109. (8) 'Acadian Geology.' Dawson. Pp. 641-657. (9) "Guide to the Geology of New York," Lincklaen; and "Contributions to the Palæontology of New York," James Hall.--'Fourteenth Report on the State Cabinet.' 1861. (10) 'Palæozoic Fossils of Canada.' Billings. 1865. (11) 'Manual of Geology.' Dana. Pp. 166-182. 2d ed. 1875. (12) "Geology of North Wales," Ramsay; with Appendix on the Fossils, Salter.--'Memoirs of the Geological Survey of Great Britain,' vol. iii. 1866. (13) "On the Ancient Rocks of the St David's Promontory, South Wales, and their Fossil Contents." Harkness and Hicks.--' Quart. Journ. Geol. Soc.,' xxvii. 384-402. 1871. (14) "On the Tremadoc Rocks in the Neighbourhood of St David's, South Wales, and their Fossil Contents." Hicks.--'Quart. Journ. Geol. Soc.,' xxix. 39-52. 1873. In the above list, allusion has necessarily been omitted to numerous works and memoirs on the Cambrian deposits of Sweden and Norway, Central Europe, Russia, Spain, and various parts of North America, as well as to a number of important papers on the British Cambrian strata by various well-known observers. Amongst these latter may be mentioned memoirs by Prof. Phillips, and Messrs Salter, Hicks, Belt, Plant, Homfray, Ash, Holl, &c. CHAPTER IX. THE LOWER SILURIAN PERIOD.