March 31, 1899.] 



SCIENCE. 



483 



As the streams of this region have an impor- 

 tant bearing upon the underground flow of 

 water, the Rio Frio has been selected as a type 

 and described in detail. " The caletas and up- 

 per cauj'ous are usually dry and waterless ar- 

 royos, except in time of storm. The flat-bot- 

 tomed canyons contain permanent pools of 

 flowing water, fed by springs and on the lower 

 plain the running water disappears entirely or 

 for a considerable distance." , 



Brief mention is also made of the caverns of 

 the plateau, as they likewise are concerned 

 with the question of underground waters. Three 

 types are recognized : " (1) small cavities within 

 individual limestone strata, giving them what is 

 locally termed a honeycombed structure ; (2) 

 open caverns occuring in certain bluff faces 

 along the stream valleys ; (3) underground 

 caverns of vast extent dissolved out of many 

 strata. ' ' 



The flora is next discussed. It presents three 

 phases : that of the stream bottoms ; " that of 

 the breaks, and that of the summit." Among 

 the interesting facts recorded mention may be 

 made of one : the occurrence of the cypress. 

 " This tree, which ordinarily grows only in the 

 swamps and bayous of the low subcoastal re- 

 gions, attains an enormous size at the edge of 

 the deeper holes near the heads of permanent 

 water of the Pedernalis, Blanco, San Marcos, 

 Guadalupe, Cypress, Onion Creek and other 

 streams. These localities are at altitudes from 

 1,000 to 1,750 feet above the sea, and hundreds 

 of miles west of the great cypress swamps of 

 the eastern tier of Texan counties, with which 

 they have no possible continuity. ■:;«■*«• 



" Before entering upon the geology of the re- 

 gion a few pages are devoted to a statement of 

 'the general principals of artesian waters.' 

 Under the caption ' Capacity of Rocks for Ab- 

 sorbing Moisture ' the following succinct state- 

 ment is given concerning the water-bearing 

 strata of Texas : ' ' The artesian water-bearing 

 strata of the State east of the Pecos River are 

 composed mostly of extensive sheets of sands, 

 clays and limestones, succeeding one another 

 in orderly arrangement, except along the Bal- 

 cones zone of faulting, and in genei'al having 

 a gentle inclination towards the sea, so that in 

 travelling northwestward, although constantly 



ascending in altitude, one encounters the out- 

 cropjjing edges of rock sheets of lower and 

 lower stratigraphic position. This produces 

 the simple arrangement of a tilted plain built 

 up of a series of alternately impervious and 

 pervious layers. The rain falling upon the out- 

 cropping edges of the latter sinks into the 

 embed and by gravity is conducted seaward 

 down the plain of its inclination to lower levels 

 beneath the sui'face. Each different stratum, 

 including any particular water-bearing stratum, 

 becomes embedded deeper and deeper to the 

 southeastward of the point where it outcrops at 

 the surface." 



The rocks appearing in the region under dis- 

 cussion are tabulated as follows : 



" Recent. 



"Wash deposits of the hillsides, stream-bed ma- 

 terial, etc. 

 Pleistocene. 



Onion Creek marl ; Leona forraatiou, and other 

 terrace deposits. 

 Pliocene. 



Uvalde formation. 

 Eocene. 

 Cketaceous. 

 Gulf Series. 

 Webberville and Eagle Pass ") 



formations | Mo^^ana division. 



Taylor and Anacacno forma- 

 tions J 



Austin chalk \ ri \ j t ■,• 



T-, , r. J 1 1 V Colorado division. 



Eagle Ford shales J 



Comanche Series. 



Shoal Creek limestone 1 



Del Rio clay v Washita division. 



Fort Worth limestone J 



Edwards limestone... "i F^ederioksburg 



Comanche Peak limestone. ... > division 



Walnut formation J 



Glen Rose formation "j 



Travis Peak and allied forma- [ Trinitj'division." 

 tions J 



Most of the above formations are minutely 

 described, especially the Cretaceous, and many 

 measured sections given. The carefully exe- 

 cuted work about Austin will be extremely 

 valuable to students, as that locality affords a 

 most inviting field for study. 



The chemical lime deposits merit a line in 

 passing. In many parts of Texas, where the 

 country rock is chalky, some of the calcareous 

 matter Is evidently redistributed through the 



