The Reckoning: The Triumph of Order on the Texas Outlaw Frontier

2. The Country

:: 7 :: 2 :: The Country The geology of west-central Texas, especially the presence and geological attributes of the Edwards Plateau, profoundly influenced the settlement history of the region. It controlled where reliable water was, and wasn’t, which governed where settlers located and what remained uninhabited wilderness. It controlled the natural distribution of arable soil, necessary for subsistence corn patches and kitchen gardens. It influenced the occurrence of timber, necessary for construction of frontier buildings and fences. It influenced the placement of early roads that connected frontier military establishments and towns, or left them unconnected and isolated. To understand post–Civil War settlement patterns in west-central Texas, the historian must grasp that the vast Edwards Plateau, because there was reliable water around its serrated periphery but not on its flat top, because its ragged margins were rough and rocky, and because it reached westward clear into northern Mexico, was a formidable physical and environmental barrier that retarded frontier settlement by about twenty years. The Edwards Plateau Covering more than thirty thousand square miles, the Edwards Plateau dominates the landscape of west-central Texas (see map 2). Along its northern and eastern margins, the plateau stands one hundred to three hundred feet above the adjacent rolling prairies; on its southern margins, it stands five hundred to fifteen hundred feet higher than the adjacent coastal plain of the Rio Grande embayment. It extends westward across the Pecos River, where it is sometimes called the Stockton Plateau, and to the southwest, across the Rio Grande, into northernmost Coahuila, Mexico, where it is known as the Serranía Del Burro. To the northwest it merges imperceptibly with the high plains (or Llano Estacado) of West Texas and the Texas Panhandle.1 The plateau is the topographic and geomorphic expression of a thick, widespread , flat-lying geological formation of early Cretaceous age known as the Edwards Limestone.2 This formation ranges from about four hundred feet thick on the north to about eight hundred feet thick along the southern edge of the plateau. Its limestone strata are generally harder and more resistant to weathering and erosion than the softer sandy and clayey formations that lie just beneath, assigned to the Trinity Formation, which is why the Edwards Plateau is a high-standing, Map 2. Physiography of the area of “The Reckoning.” Modified from Erwin J. Raisz landform maps (1957, 1964) with permission. 9 :: Oasis of Outlaws rough-edged geomorphic feature. Moreover, Edwards Limestone strata are susceptible to dissolution by water, hence they are, like many limestone formations, porous and permeable, and honeycombed with caves. Rainwater that falls on the plateau, rather than running off, tends to sink into the fractured, cavernous limestone, where it accumulates in the lower part of the Edwards Limestone simply because the sands and clays of the underlying Trinity Formation are much less permeable and transmissive. So, blocked from further downward movement, the down-trickling rainwater accumulates in the honeycombed lower Edwards limestones, thus forming a widespread unconfined aquifer at the base of the formation.3 It is this aquifer that is the source of copious permanent springs that constitute the headwater springflow of all the region’s rivers , and also the source from which most of the region’s windmills draw water.4 Headward-cutting streams dissect the periphery of the Edwards Plateau from the east and south. Clockwise from the north, they are the Concho, San Saba, Llano, and Pedernales (all tributaries of the Colorado River), Blanco, Guadalupe, Medina, Sabinal, Frio, East and West Nueces, and Devils Rivers. This headward dissection creates deep canyons and rugged topography around the margins of the plateau, with intervening high interfluvial divides. Strong permanent springs issue from the head of each tributary. These headwater springs are all located where the headward-cutting tributary canyons intersect the permanent groundwater table just above the base of the Edwards.5 This distinctive dissected landscape occupies an arcuate swath across central Texas, east and south of the main mass of the Edwards Plateau, and west and north of the Balcones Escarpment, known as the Texas Hill Country (see map 3). It began to be settled in the 1850s, and permanent towns soon began to be established to serve developing agriculture and commerce. To the west, the vast, flat-topped mass of the Edwards Plateau was a wilderness savanna, uninhabited precisely because there was no permanent water, no...