THE C EN O ZOIC DEPOSITS OF TEXAS. 56 1 



question, even by those better acquainted with the Cretaceous 

 than were these observers. Loughridge, in his Report on Cotton 

 Production, (Tenth Census Report), comes nearer the truth when 

 he refers it to the Port Hudson. 



The very variable series of beds intended to be included in 

 this division, has, usually, at the base a conglomerate of pebbles 

 of various sizes, imbedded in a lime matrix, often indurated, 

 sometimes tufaceous, sandy or even clayey. Above this is often, 

 but not always, a series of interbedded clays, limy clays, limy 

 sands and sandstones with some pebbles. This closely resembles 

 the Lagarto clays. The whole is capped by the Reynosa lime- 

 stone. This is a tufaceous lime rock, but often so mixed with clay 

 or sand as to lose that character. There are few exposures which 

 show the entire series of beds. In places along the middle Rio 

 Grande, the basal bed of conglomerate is all that is present, 

 while on the divides the basal and uppermost beds are usually 

 found, but without the intermediate Lao;arto. 



The Reynosa, in its typical form, is only found west of the 

 Colorado, so far as I have observed. East of the Guadalupe the 

 lime is gradually replaced by iron, the Orange sand phase appears 

 in the Colorado drainage and east of that stream becomes the 

 prevailing form, although some lime is present at many localities. 

 This change is obviously due to the fact that in the western part 

 of the State the erosion of the Cretaceous limestones furnished 

 the materials for the Reynosa, while in the east the ferruginous 

 beds of the Tertiary supplied the materials for the Orange sand. 



No fossils have been found in this deposit which can certainly 

 be said to be indigenous to it. A number of shells of Bulimus 

 were found imbedded in an upper crumbly layer of it, but they 

 are simply on the surface and are probably later. 



No other bed of the Tertiary has anything like so wide a dis- 

 tribution as this. I found it at the top of the escarpment of the 

 Llano Estacado in Garza county, at the point marked " 1 1 " on 

 the map of the Llano Estacado accompanying the Third Annual 

 Report of this Survey, and also just south of Big Springs, resting 

 on the northern slope of the Cretaceous hills. Cummins has 



