CLIMATOLOGY OF THE LATE PALEOZOIC 249 



"2. The plant fossils^ in the Wichita red beds of Texas and some other 'Red 

 Beds ' show no xerophytic adaptations. On the contrary ' red beds ' are associated 

 with coal deposits in various parts of the world. 



"3. The amphibians and reptiles of Wichita time and the vertebrate fossils 

 in some other ' red beds ' were land animals which lived part of the time in water, 

 part of the time on land. They did not live in a desert environment. 



"But the presence of widespread deposits of salt and gypsum, of practically 

 incontestable sedimentary origin, contemporaneous with the red clays, seemed 

 to indicate conditions of aridity in at least later Permian time in Texas and else- 

 where. Therefore, two working hypotheses were formulated to account for the 

 conditions: (i) That the 'red bed' sediments were not originally red, but had 

 in some way been changed to a red color subsequent to their deposition ; (2) that 

 the 'red beds' associated with the salt and gypsum were derived from old residual 

 soils of moist warm climates, transported and deposited without change of color 

 in the arid basins of the later Permian. 



"At the time of the original investigation it seemed impossible to make a 

 definite choice between these two hypotheses, and so the further investigation 

 was held in abeyance. In more recent years, the examinations of samples from 

 deep borings in the 'red beds' of Texas by Dr. J. A. Udden,^ has demonstrated 

 the persistence of the red color in depth. So, although in some instances the red 

 color may be secondary, in the red beds of Texas it is almost certainly primary, 

 i. e., contemporaneous with the deposition of the sediments. Later, a re-examina- 

 tion in the light of late evidence of later Pennsylvanian and Permian geologic 

 history of Texas has shown that the second hypotheses can be consistently 

 advanced as the solution of the problem." 



The lateral transition from light-colored sediments into red beds, typic- 

 ally along the Kansas-Oklahoma line, so often repeated, is also a point in 

 evidence. 



The very names used by well-drillers for certain horizons in Pennsylvania 

 and West Virginia, as "deep red" shows that the color holds in the east and 

 is original. Another convincing evidence of the original red color of the 

 shales and sandstones has been noted by the author wherever he has seen 

 red beds of Permo-Carboniferous age, from Prince Edward Island to Arizona. 

 The red shales are frequently mottled by light blue or green dots, circular in 

 section and evidently spherical in the undisturbed rocks. These are found 

 in freshly fractured surfaces of fragments taken from the bottom of excava- 

 tions so deep as to be beyond the reach of surface-waters. The only explana- 

 tion for these spots is the presence of small bits of organic matter which 

 reduced the ferric oxide after deposition. In other specimens from similar 

 localities the light green or blue color appears in blotches and irregular 

 patches, but all with sharply defined limits. In masses of hard red shale 

 or sandstone nearer the surface the edges of cracks, both horizontal and 

 vertical, have the same light green or blue color, due to the infiltration of 

 surface-waters carrying organic matter. 



^ White, David, Jour. Geol., vol. xvii, pp. 320-341. 



^ Udden, J. A., The Deep Boring at Spur, Bull. Bur. Ec. Geol. and Techn., Univ. of Texas, 

 1914, No. 363. Potash in the Texas Permian, Ibid., No. 17, 1915. 



