ARKANSAS HISTORICAL QUARTERLY; Volume 20, Spring 1961   Thomas Jefferson and the Louisiana-Arkansas Frontier   BY MILFORD F. ALLEN Arkadelphia, Arkansas   THE PERIOD FROM 1800 TO 1840 MAY BE CALLED THE PIONEER-NATURALIST PHASE IN the history of American science. It was a period of collecting and naming, a time of assembling the data that was necessary to the formulation of subsequent theory and law. "The dominant emphasis among all teachers of natural history was the classification of minerals, plants, and animals." (1) The collector and classifier was a naturalist-scientist with an interest in all knowledge; and natural history--which can be used interchangeably with the term science--took in practically all of science, including biology and geology. In 1800 the primitive American wilderness beckoned, haunted the mind, and intoxicated the early naturalists with its wealth of new botanical, zoological, and geological material. A man to lend the power of government to its exploration was Thomas Jefferson. Jefferson's great interest in the exploration of the West was natural to a man who was himself something of a scientist. ____________________ * Dr. Allen is Chairman of the Division of Social Science at Ouachita Baptist College. 1. William Martin Smallwood, Natural History and the American Mind (New York, 1941, 288. Most authorities mark the 1840's as the end of the naturalist period and the beginning of specialization and the logically organized branches of science.         Contents  Words  Study Questions  Related Sites  Next Page