Geology Impacts History: Influence of the Edwards Plateau on Frontier History of the Texas Hill Country
Rose, Peter R.
The geological attributes and presence of the Edwards Plateau exerted a powerful influence on the history of the Texas Hill Country during the late 19th century. The Plateau is an immense tableland that covers more than 25,000 square miles of west-central Texas, the geomorphic expression of the resistant Edwards Limestone. Rainfall sinks into permeable limestone terranes on top of the Plateau rather than running off. Because the formations underlying the porous Edwards Limestone are relatively impervious, water accumulates in the lower Edwards, forming an extensive unconfined regional aquifer which is the source of all the springs around the Plateau margins The consequences of this geology are unusual: a vast, elevated, waterless plain, dissected around its margins by limestone canyons fed by perennial springs that form the headwaters of all the rivers in central Texas.
Because of its rugged margins and the absence of dependable surface water on top, the Plateau was a formidable wilderness barrier to permanent habitation. Early regional roads, as well as the Western Beef Trail, mostly skirted the Plateau. Marauding Indians used the thick-turfed plateau uplands as wilderness war trails to fall suddenly upon unsuspecting settlements around the plateau margins, thus inhibiting permanent settlement.
In 1873, opportunistic Anglo-Celtic cattlemen and homesteaders began settling the apron of stream-laced lands that bordered the Edwards Plateau on the east. Criminal confederations took root in isolated locations for many reasons: 1) sparse population; 2) lack of organized government and Law; 3) access to northbound trail herds; 4) clandestine livestock markets along the Mexican border; 5) abundant hiding places around the dissected margins of the Plateau; and 6) adjacent wilderness as a waiting refuge from pursuing lawmen.
Sustained campaigns by Texas Rangers, aiding fearful settlers and beleaguered county lawmen, gradually brought order to the region. New technologies ended the friontier period. Regional railroads skirting the Edwards Plateau put an end to the cattle drives. The plateau uplands began to be settled when cable-tool drilling and windmills provided reliable water from the Edwards aquifer, and barbed wire allowed ranchers to control grazing. The frontier era in the western Hill Country was over.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013