R. T. HILT. — THE TEXAS-NEW MEXICAN REGION. 87 



their lorn;- and different journeys t<> the sea, an mini the salients of the north western 

 escarpment of the Llano Estacado, which looms up in the distance like a majestic 

 wall. Language cannot describe the magnificence of the scenery here. Everywhere 

 is seen the grand results of profound erosion, by which the overlapping formations 

 (Dakota, Denison and Trinity beds) have been stripped from the horizontal Red 

 beds, which constitute the valley floor, and has left standing in the valley numerous 

 remnants of the plain in the shape of great circular buttes and mesas, such as El 

 Corazon, the Gavilan, Mesa Rico, Mesa Redondo, the big and little Huerfano, Mesa 

 Tucumcari and others, every stratum of their red, brown and white beds being 

 visible in horizontal hands for scores of miles. 



The western border is the foothills or hogbacks of the eastern front of the Rockies. 

 The northern border from Trinidad to Folsom is the northern escarpment of the so- 

 called Raton mesa, the foot of which is followed by the Denver and Fort "Worth 

 railway. The eastern border is less conspicuous, for it is the haseleveled shore line 

 of the Llano Estacado formation. 



This region possesses a diverse surface aspect, consisting as it does of various 

 erosion plains upon which stand great remnantal mesas of sedimentary and eruptive 

 rock sheets, like Raton mountain and Fishers peak — remnants of the atmospheric 

 erosion of Tertiary and Pleistocene time. The region as a whole, however, is a 

 series of stratigraphic plains produced by degradation from one hard bed of strati- 

 fication to another in successive steps from the Fishers peak basaltic sheet, which 

 caps the highest mesas, to the Laramie sandstones; from these to the calcareous 

 flaggy layers of the Colorado shales, as at Springer and Las Vegas ; and from these 

 down to the basal Dakota sandstone's with the white hand of the Trinity which 

 forms the foundation of the series, as in the Canadian valley and the accompanying 

 Corazon escarpment. The Red lied floor is finally reached, below the white hand 

 of Trinity sandstone, some 10,000 feet below the highesl summit of the old plateau. 



The plateau or shoulder as a whole is a product, then, of the unequal erosion of 

 the sub-horizontal beds of the upper Cretaceous from the Laramie to the Dakota, 

 inclusive, which are here included between the Red lied floor and the Fishers peak 

 basalt. This erosion from top to bottom of the successive plains of stratification has 

 partially removed more than 5,000 feet in thickness of sedimentary strata; and 

 there is no evidence that the region has ever been submerged since Cretaceous time, 

 either during the Llano Estacado or the basin epochs mentioned elsewhere. In 

 fact, it was the stream-worked land whose del iris furnished much of the sediment 

 for the rocks of the last-mentioned periods. It is the remnant of a great plateau 

 (the Tertiary land) which existed around the southern half of the Rocky mountain 

 uplift before the Llano Estacado (Neocene) epoch, during which the larger mass of 

 the plateau was degraded or haseleveled and was the shore line of the yreat coastal 

 plain now represented in the Llano Estacado deposits. During this epoch much of 

 its unconsolidated mass was removed, and reappears as the silt of the Llano Estacado 

 formation, 'the later Pleistocene erosion has still further degraded the plateau and 

 reduced its thickness and extent. 



Tin-: Llano Estacado. 



For those portions of the greal plains proper lying easl of the Raton-Las Vegas 

 plateau, south of the Cimarron river and east of the Pecos, the term Llano Esta- 

 cado was appropriately applied by the early Spanish explorers, but the term is now 

 usually restricted to the portions south of the Canadian. In surface features the 



