The product of intellectual effort appears to be conditioned by time of planting and character of soil as well as by quantity of seed. For example: Erosion by rivers was as clearly shown by Desmarest as by Dana and Newberry 50 years later. Criteria for the recognition of ancient fluviatile deposits were established by James Deane in 1847 in a study of the Connecticut Valley Triassic. Agassiz’s proof that ice is an essential factor in the formation of till is substantially a duplication of Dobson’s observations (1826). The volumes of the Journal with their very large number of articles and reviews dealing with geology show that the interpretation of land forms as products of subaërial erosion began in France and French Switzerland during the later part of the eighteenth century as a phase of the intellectual emancipation following the Revolution. Scotland and England assumed the leadership for the first half of the nineteenth century, and the first 100 volumes of the Journal show the profound influence of English and French teaching. In America, independent thinking, early exercised by the few, became general with the establishment of the Federal survey, the increase in university departments, geological societies and periodicals, and has given to Americans the responsibilities of teachers. _Bibliography._ (In the following list “this Journal” refers to the American Journal of Science.) Footnote 4: Wilson, J. W., Bursting of lakes through mountains, this Journal, =3=, 253, 1821. Footnote 5: Whitney, J. D., Progress of the Geological Survey of California, this Journal, =38=, 263–264, 1864. Footnote 6: Playfair, John, Illustrations of the Huttonian theory of the earth, Edinburgh, 1802. Footnote 7: Kain, J. H., Remarks on the mineralogy and geology of northwestern Virginia and eastern Tennessee, this Journal, =1=, 60–67, 1819. Footnote 8: Hitchcock, Edward, Geology, etc., of regions contiguous to the Connecticut, this Journal, =7=, 1–30, 1824. Footnote 9: Buckland, Wm., Reliquiæ diluvianæ, this Journal, =8=, 150, 317, 1824. Footnote 10: Phillips, John, Geology of Yorkshire, this Journal, =21=, 17–20, 1832. Footnote 11: Scrope, G. P., Excavation of valleys, Geol. Soc., London, No. =14=, 1830. Footnote 12: Hayes, G. E., Remarks on geology and topography of western New York, this Journal, =35=, 88–91, 1839. Footnote 13: Seventh Meeting of the British Association for the Advancement of Science, this Journal, =33=, 288, 1838. Footnote 14: Darwin, Charles, Geological observations on the volcanic islands and parts of South America, etc., second part of the Voyage of the “Beagle,” during 1832–1836. London, 1844. Footnote 15: Hildreth, S. P., Observations, etc., valley of the Ohio, this Journal, =29=, 1–148, 1836. Footnote 16: