xlviii REPORT OF THE STATE GEOLOGIST. 



stone, etc. Through the center of the thick shales rises an immense 

 chimney of dark red porphyry. Inocerami and Ammonites of distinct- 

 ively characteristic forms were found here. 



LOWER CROSS TIMBER SAND. 



To the west and immediately below these clays as they occur east 

 of the Brazos Eiver, is found a series of sandy materials, whose areal 

 extent is coincident with the timbers from which they receive their 

 name. Sometimes they are ferruginated and also contain small de- 

 posits of lignite and particles of iron ore. The sands are frequently 

 cross-bedded, and their whole formation tells of the littoral or near- 

 shore conditions, which mark the beginning of the Upper Cretaceous 

 subsidence. The soils, although sandy, sustain a rich timber growth, 

 and are most suitable for the growing of fruit trees. 



The Lower Cross Timbers or Dakota sandstones are represented in 

 the foothills of the Diabolo Mountains, about four miles north of Eagle 

 Flat, by a series of sandstone hills from two to four hundred feet in 

 height, the stone of which is composed of rather coarse, sharp sands, 

 white or yellow in color and weathering brown through oxidation of 

 its iron. It carries a few pebbles in places, has some few seams of 

 calcareous sandstone, and shows slight cross-bedding. This sandstone 

 rests directly upon limestones containing fossils characteristic of the 

 Washita Beds, but no fossils were found in the sands themselves. It 

 was assigned to this position from its stratigraphic relations only. 



In the Upper Cretaceous Series we have, outside the great fertility of 

 its soils and its structural materials, which have already been men- 

 tioned, and the coal found in the neighborhood of Eagle Pass, which is 

 described below, very little which at present can be described as 

 being of economic value. Indications of petroleum and gas are found 

 in places, but there is not sufficient data now in hand to make positive 

 statements regarding them. The possible use of its chalks and marls 

 as fertilizers on other lands of the State has also been referred to, and 

 there only remains one resource, which is nevertheless one of the great- 

 est importance, that is, artesian water. Throughout this whole area of 

 the Upper Cretaceous as mapped herein there exists not only the pos- 

 sibility of securing artesian water at reasonable depths, but in the 

 greater number of localities the certainty of doing so. The places at 

 which it can not be gotten, owing to adverse topographic conditions or 



