Vegetation Aids for Recognizing Boundaries of Glacial Features

between the growing trade and population centers discloses a rather close correlation of roads and trade centers with natural geographic regions thus justifying the suggestion that administrative units, whether private, state, or federal, operate at their greatest advantage when their institutional boundaries are made to conform to the natural boundaries of their respective units (Fig. 5). Had the Morman Pioneers known more of the physical base upon which they hoped to build their great empire sncl its attending political and social institutions, they likely would not have arbitrarily divided the territory into a series of great linear belts for administrative purposes, but would have let natural geographic features guide them in the designation of units upon which their institutions hoped to find anchorage. BIBLIOGRAPHY Bancroft, Herbert Howe: "History of Utah." Compiled Laws of Utah, 1855, 188S, 1907, 1917. First Annual, and Special Sessions of the Legislative Assembly of the Territory . of Utah, 1855. Hansen, George H.: "A Regional Redistricting Plan for the State of Utah." Jenson, Andrew: "L. D. S. Church Chronology ." Laws of the Territory of Utah, 1856, 1861, MIDPOINTS BETWEEN TRADE CENTERS MIDPOINTS ON rcDCHAU HlOHWATi BCIWCCH THAOC CCHTtBS F -I- # UIDCOIMT»—»-¦— MIkCADC \ I ..V. ¦"????G???-,?.1862 , 1864, 1866, 1867, 1868, 1869, 1870, 1872, 1876, 1880, 1882, 1884, 1888, 1890, 1892, 1894. Laws of Utah, 1913, 1917, 1919, 1921, ?931. Ordinances of the State of Deseret, 1850 (Volume entitled "Constitution of the State of Deseret"). Tullidge: "History of Utah" (vol. 1 & 2). Utah State Road Commission, 1935. Whitney, Orson F.: "History of Utah" vol. 1, 2, & 3). Young, Levi Edgar: "Founding of Utah." Vegetation Aids for Recognizing Boundaries of Glacial Features W. E. KIRKENDALL University of Colorado, Boulder, Colorado Vegetation, though seldom mentioned or credited in final writings, has served many a field worker in his efforts to untangle the evidence of Pleistocene glacial advances. Many early publications on Pleistocene glaciology seem to have been written from the observation car platform. From this point of view, floral cover must have ranged with topographic form and position as factors used in identification of glacial deposits. These arm chair field trips left a bad taste in the mouths of younger, more energetic field workers, who, swinging to the other extremes, insisted on detailed geologic study of the entire boundaries of each deposit. It should not be assumed that vegetation can or will replace careful field investigation of glacial deposits; nevertheless , it may be used as an aid in the recognition of and mapping of the glacial boundary. With the many areas of glacial deposits as yet untouched by field work, reconnaissance mapping seems both necessary and practical. These maps should depend upon geological work as well as visual aids. Contacts between different gla** (8) cial deposits should be mapped and studied at numerous points, but, often, time and finances do not permit detailed mapping. By noting the types of vegetation characteristic of the different glacial deposits, one can often retire to some distant, elevated position, and, using the vegetation as an aid, connect the units that have been intensively studied. In this way the contacts between deposits can be drawn quite accurately and quickly. Field studies that prompted this paper were- confined to the semi-arid regions in. or near the eastern boundaries of the Rocky Mountains in, the states of Colorado, Wyoming, Montana , and the Province of Alberta. Physical factors of the environment are remarkably similar throughout this whole region. The elevation of the respective landscapes, of course, decreases from 9,000 feet in Colorado to 4,000 feet in Alberta. With the exception of Colorado, the precipitation is near the critical amount that divides scrub and tree growth from grassland . Because of this amount of moisture , the type of vegetation depends upon the drainage, soil development, and the exposure to rain-bearing winds. The recognition of two distinct glacial advances' permitted a careful study of contrasting vegetation on two out wash plains and associated moraines. The most recently deposited outwash plains (Wisconsin?) were covered with a luxuriant growth of grass. Where these plains extend beyond the mountain front the areas are relatively level or gently rolling and are covered with a thick sod. Where similar outwash is deposited¡n valley...