12. Prepare suitable geological sections.
Reading Reference
William H. Hobbs. Apparatus for Instruction in Geography and Structural Geology. III. The Interpretation of Geologic Maps. School Science and Mathematics, vol. 9, 1909, pp. 644-653.
APPENDIX E
SUGGESTED ITINERARIES FOR PILGRIMAGES TO STUDY EARTH FEATURES
The chief value of the laboratory studies discussed in the preceding appendices is as a preparation for observations made in the field—the laboratory par excellence of the geologist. The pilgrimages whose itineraries are here suggested have been planned especially for impressing by observation the lessons of this book. Such journeys are best interrupted at a relatively small number of localities which, because already studied in some detail, are specially adapted to serve as centers for local excursions. These localities will in most cases be the great scenic places to which tourists resort, or the seats of universities near which specially detailed explorations have been often made.
Within the United States a few local geological guides have been published, and the Geologic Folios published by the United States Geological Survey are already available for a number of such centers. For one long geological pilgrimage we are fortunate in having a carefully prepared guide, namely, from New York to the Yellowstone National Park and back, with a side trip to the Grand Cañon of the Colorado. Except for the side trip this route, in large measure, corresponds with one here chosen, and for the return journey especially the student is referred to it for information (Geological Guide Book of the Rocky Mountain Excursion, edited by Samuel Franklin Emmons. Comte Rendu de la Congrés Géologique Internationale, 5me Session, Washington, 1891, 1893, pp. 253-487, map and plates 13, figs. 32).
Our journey is begun at New York City, which is built about the deeply submerged channels of an estuary choked with glacial deposits, though the channel may be followed as a deep cañon across the continental shelf to its margin ([252],[4] [pl. 17 B]). New York City is also upon the margin of the glaciated area, the outer terminal moraine of which is well represented on Long Island ([298]). Across the Hudson in New Jersey is the great Coastal Plain which meets the oldland in a well-defined margin ([159], [246], [247]). A local geological guide of the vicinity of the metropolis has been written by Gratacap (Geology of the City of New York, Greater New York. Brentanos, New York, 1904, pp. 119, pls. and map).