From 1871 to 1875 W. F. Roberts, George Haddock, William C. Hazeldine, Arnold Syberg were successively State Geologists. One report was published by George Haddock in 1872.

From 1887 to 1893 John C. Branner was State Geologist and during that time, with the help of assistants, there were issued fourteen volumes of reports on various phases of the mineral wealth of the State.

From 1907 to 1923 the Professors of Geology of the University of Arkansas, A. H. Purdue, N. F. Drake, G. H. Cady, served successively under the law as ex-officio State Geologists, and devoted a portion of their time to the State work. During the regime of A. H. Purdue three volumes of reports were published.

The present Survey was established by Act of the Legislature approved March 22, 1923, and the present State Geologist was appointed July 2, 1923..

Prior to July 1, 1927, the expense of the State Geological Survey was defrayed from the general revenue fund. The Forty-sixth General Assembly passed an Act creating a special revenue for the support of the departments, which consists of a one-tenth of one per cent increase in the severance tax on all minerals except coal and manganese. The rate on manganese was increased one mill per ton. The one-cent-a-ton tax on coal was not increased.

General Physical Features of Arkansas

PHYSIOGRAPHY

Arkansas lies in two major physiographic divisions of southern United States. The southwestern and eastern portions of the State lie in the Gulf Coastal Plain or lowland area, and the northern and western portions lie in the interior highland area comprising the Ozark region, the Ouachita Mountains, the Arkansas Valley and the Athens Plateau. The dividing line between these two great divisions enters the northeast corner of the State near Pitman, Randolph County, and crosses Arkansas in a southwesterly direction, passing near Newport, Searcy, Little Rock, Arkadelphia, and thence nearly due west, slightly north of De Queen, into Oklahoma.

The Gulf Coastal Plain occupies about 27,370 square miles, or about 52 per cent of the area of the State, and the highland area 25,155 square miles or 48 per cent of the total State area.

The Ozark region is an uplift, having an area of about 50,000 square miles of somewhat irregular oval shape, which lies in northern Arkansas, southern Missouri and northeastern Oklahoma. The Boston Mountains occupy the southern and southwestern flank of the Ozark region in northern Arkansas and northeastern Oklahoma and.

passing northward, the Springfield and Salem Plateaus make up the remainder of the Ozark region of the State.

The Ouachita Mountain system covers a broad belt, for the most part of fairly regular east-west ridges and is some thirty to fifty miles in width. The region extends from between Little Rock and Malvern westward about 320 miles to the vicinity of Atoka, Oklahoma.

The Arkansas River Valley region is between thirty to forty miles in width and lies between the Boston Mountains on the north and the Ouachita Mountain area on the south. It extends from the Coastal Plain border between Little Rock and Newport westward into Oklahoma, a total distance of about 300 miles.

The Athens Plateau is a belt sloping south, having a width of about fifteen miles, lying between the Ouachita Mountains and the Gulf Coastal Plain. It extends from a short distance west of Arkadelphia westward into Oklahoma.

TOPOGRAPHY

The topography of Arkansas naturally falls into two main divisions, the lowland area and the mountainous or highland area. The lowland area corresponds to the Gulf Coastal Plain region of western and southern Arkansas, described as one of the main physiographic divisions of the State. This is a relatively low, south sloping plain, the elevations of which vary from about 100 to 700 feet above sea level. The western portion of this plain is a rolling, hilly country intersected by south and southeastward flowing streams, elevated for the most part between 200 and 400 feet above sea level. The eastern and northeastern portion is a comparatively level plain with the exception of Crowley's Ridge, which is the one outstanding topographic feature of eastern Arkansas. The elevation of the plains area varies from 100 to 300 feet. Crowley's Ridge is an erosional ridge extending from west of Cairo, Illinois, to near Helena, Phillips County, a distance of about 200 miles. Its elevation above the adjacent lowlands in Arkansas averages about 200 feet. Its elevation above sea level varies from about 400 to 500 feet, the higher portions lying in the northern part of the Coastal Plain.

The northwestern half of the State, or highland area, topographically may be separated into (1) the Ozark region, which includes the Boston Mountains, the Springfield and Salem Plateaus; (2) the Arkansas Valley, which is a broad synclinal trough lying south of the Boston Mountains; (3) the Ouachita Mountain system of central and western Arkansas, and (4) the Athens Plateau, which lies between the Ouachita Mountains and the Coastal Plain.

The Ozark region of Arkansas is generally divided into three topographic divisions, (1) the Boston Mountains, (2) the Springfield Plateau, and (3) the Salem Plateau.

The Boston Mountain area occupies approximately the southern third of the Ozark region of Arkansas and extends westward from near Newport for about 200 miles into Oklahoma, terminating in the western portion of Sequoyah County, Oklahoma. The average width of this area is about thirty miles. The mountains of the region. are much cut up and dissected by drainage and are rugged and irregular. They consist usually of northward and southward branching spurs from a main east-west mountainous backbone which constitutes the main watershed between the Arkansas and White River drainage basin. This applies particularly to the Boston Mountain region of western Arkansas. Summits of the mountains in this area usually vary in altitude from 1,850 to 2,250 feet above sea level. The elevations of two mountains in northwestern Newton County, according to the U. S. Geological Survey, are 2,400 feet. The elevation of the mountains above the adjacent lowlands varies from 500 to 1,300 feet. The Boston Mountain area grades gradually into the Arkansas Valley on the south, but on the north it forms what is often an abrupt escarpment overlooking the Springfield Plateau area. The Boston Mountains constitute the highest land area in the Ozark region, an aggregate of about 5,000 square miles, while the total in Oklahoma is about 2,000 square miles.

The Springfield Plateau is an intermediate topographic division lying between the northern border of the Boston Mountains and the Salem Plateau, which makes up the larger portion of the Ozark region. The Springfield Plateau in the eastern portion of the Ozark region of Arkansas is quite narrow and winding, varying between five miles and twenty-five miles in width, while in the northwestern corner of the State it broadens to a width of about forty miles and extends westward into Oklahoma and northward into Missouri, covering a total area of about 12,000 square miles. The higher portions of the Springfield Plateau are largely made up of siliceous beds of a resistant nature and at one time probably constituted a somewhat level plain. At present, however, the Arkansas portion of the Plateau has been eroded by the drainage of the region so that it is cut by numerous streams of the White River basin. The northeastern portion of the Plateau in Arkansas is a gently rolling country. The height above sea level of this Plateau usually varies between 1,250 and 1,700 feet.

The Salem Plateau makes up a third and the largest, as well as the lowest, division as a whole, of the Ozark region. It covers approximately 31,000 square miles in northeastern Arkansas and Missouri. The Salem Plateau region of Arkansas occupies a triangle which is bounded on the north by the Missouri-Arkansas line, on the east by the border of the Gulf Coastal Plain of Arkansas, and on the southwest by a line roughly approximating the course of the White River. The topography of this region is usually not so precipitous as that of the Springfield Plateau or Boston Mountain region. Small pocket-shaped areas of the Plateau extend into Arkansas in northern