As a result of the oscillations just referred to, the sea has gained important characteristics as well as the land. The broad submerged shelf fringing the continent furnishes conditions highly favourable to both plant and animal life, and affords some of the most valuable fishing-banks of the world.
The Caribbean region is a marked exception to the broader changes that have affected the coast-line throughout the central and northern portions of the continent, and stands by itself as a conspicuous illustration of more localized earth movements which produced a remarkable submarine topography.
In continuation of the studies outlined in this chapter the following books, most of which contain more special references, will be found of assistance:
AGASSIZ, A. _Three Cruises of the Blake._ 2 vols. Houghton, Mifflin & Co., Boston, 1888.
GILBERT, G. K. _The Topographic Features of Lake Shores._ In United States Geological Survey, Fifth Annual Report, 1883-'84, pp. 69-123.
GULLIVER, F. P. _Shoreline Topography._ In Proceedings of the American Academy of Arts and Sciences, vol. xxxiv, 1899, pp. 151-258. Contains a valuable bibliography.
HILL, R. T. _The Geological History of the Isthmus of Panama and Portions of Costa Rica._ Bulletin of the Museum of Comparative Zoology at Harvard College, vol. xxviii, 1898, pp. 151-285.
HILL, R. T. _Cuba and Porto Rico with the Other Islands of the West Indies._ The Century Co., New York, 1899.
SHALER, N. S. _Seacoast Swamps of the Eastern United States._ In United States Geological Survey, Sixth Annual Report, 1884-'85, pp. 353-398.
SHALER, N. S. _The Geological History of Harbors._ In United States Geological Survey, Thirteenth Annual Report, Part II, 1891-'92, pp. 93-209.
SHALER, N. S. _Sea and Land._ Scribner, New York, 1894. _United States Coast and Geodetic Survey._ Annual Reports, Coast Pilot, Tide Tables, etc.
To the student of the geography of the coast and submerged border of North America, the extensive series of charts published by the _United States Coast and Geodetic Survey_ supply a vast amount of accurate information. A catalogue of these charts, with prices, etc., is issued by the Survey. Many of the charts issued by the _United States Hydrographic Office_, and a large number of the topographic maps published by the _United States Geological Survey_, are of value in this same connection. An account of these charts and maps, with instructions as to methods of obtaining them, etc., is given in _Government Maps for Use in Schools_, by Messrs. Davis, King, and Collie, published by H. Holt & Co., New York, 1894.