BY A. (iIBB MAITLAND, C.E., F.G.S.' 26 



<eveii at places fully 400 miles from the Gulf coast. The general 

 dip of the strata, in and around the Gulf of Mexico, to the east 

 of the PalfBozoic area, is towards the present outline of the Gulf 

 coast, at a very slight angle, a little greater than the slope of 

 the surfatte ; the beds to the west of the raheozoic area have a 

 gentle dip to the west. 



The Cretaceous beds are largely developed in Texas, and 

 portions have been studied in considerable detail in sonie 

 localities, more especially in the neighbourhood of the Colorado 

 River. 



In this neighbourhood the base of the Lower Cretaceous 

 ■consists of a group of rocks made up for the most part of sand- 

 stones, coarse conglomerates, and grits, separated by impervious 

 argillaceous limestone and calcareous sandstone. This series is 

 known by the name of the Trinity Sands, or Upper Cross 

 Timbers. These strata are the great water-receiving beds of 

 Texas, and, owing to the outcrop consisting chiefly of unconsoli- 

 dated sands, nearly every drop of rain which falls upon them is 

 absorbed and transmitted underground. The thickness of the 

 Trinity Sands varies from 300ft. to 600ft. 



The Upper Cross Timber Series (or the Trinity and Paluxy 

 Sands), enters the State on the western border of Arkansas, and 

 •occupies a comparatively narrow strip of country, extending east- 

 ward as far as the Onachita Mountains, from whence it sweeps 

 round to the south, with an outcrop of varying width, through 

 the towns of Millsap, Dublin, Burnett, and Travis Peak, to 

 somewhere about the 30th parallel of latitude, where the tongue 

 of older Palaeozoic rocks ends. The Trinity Sands form con- 

 spicuous escarpments, resting directly upon the Palaeozoic rocks 

 at altitudes varying from 650ft. to looOft. above sea level. In 

 some localities the catchment area is rarely more than half a 

 mile in width. In nearly every county between the 97th and 

 98th meridians and to the east of the outcrop, artesian water has 

 been obtained in wells at depths varying from ,200ft. to 2.000ft. 

 (Plate II, fig. 1). 



Further to the east of these beds is the outcrop of the 

 Dakota Sands, or Lower Cross Timber Series, forming the base 

 of the Upper Cretaceous formation. The Dakota Sands consist 

 in this region of white sandstones, sands, and sandy clays, which 



