6o THE PERMO-CARBONIFEROUS RED BEDS OF 



marine faunas. So far as my collecting in the typical Capitan limestone goes, the 

 fossils were abundant only in the purer limestones, and were very rare, or wanting 

 in what appeared to be the dolomitic portions of it. These limestones occur in the 

 Apache Mountains and at Guadalupe Point, but appear to be wanting, as does the 

 fauna, north of the Texas line; the only exceptions noted were Fusulina elongata 

 and one or two other species in Dog Canyon and Sitting Bull Canyon. From this 

 it will be seen that the fauna was closed off on the north by untoward conditions 

 and on the east by the red bed sedimentation, which constituted a barrier. No 

 other barrier is known. 



' ' Two other considerations must be taken into account. First, that the Permian 

 facies of this fauna may be an abnormally early precursor of the Permian faunas 

 developed in an isolated basin. Such an occurrence of Permian forms is known in 

 Kansas well down in deposits of Pennsylvanian age. However, the variety and 

 richness of the Guadalupian fauna, which possess such a young appearance, seem 

 to me to argue against this hypothesis. Second, the other possibility is that the 

 fauna is no older than it appears, and that it developed normally with little outside 

 connection, as did the Kansas Permian fauna. The same features as before would 

 have controlled its isolation. Much of the Red Beds being almost a land surface a 

 considerable part of the time — if we accept the subaerial origin of a large part of 

 the deposits — aggradation may have but slightly overbalanced degradation, and 

 they may have accumulated slowly for that class of sediments. Thus, though dis- 

 turbances raised the southern part of the Guadalupe limestones above sea-level, and 

 permitted their partial removal and the subsequent deposition of the upper Red 

 Beds upon the eroded surface, the fauna may well have been an early Permian 

 fauna. Until further data are at hand I am much inclined to this latter hypothesis. 

 The fact that several hundred feet of the Kansas Permian deposits grade off into 

 typical red beds in a very short distance in Oklahoma is suggestive of possible con- 

 ditions east of the Guadalupes. If such were the case, we would expect the Guada- 

 lupian faunas to cease as abruptly upon the strata changing to the Red Beds as 

 the Kansas faunas do upon entering the Oklahoma Red Beds. 



"At the same time, owing to the very nature of the origin of the Red Beds, 

 their extreme southwestern part may have been deposited slightly later than the 

 main mass farther to the north and east. However, this is regarded more in the 

 nature of a possibility than a probability. 



"The accompanying map [fig. ii] indicates the probable relationship of the 

 marine areas during Council Grove-Chase and Guadalupian time in the immediate 

 area under consideration. No attempt is made to show the full extent of deposits 

 laid down at this time. The full lines indicate marine conditions and the Unes alter- 

 nating with stippled ones continental-marine deposition. The extent to which the 

 two factors contributed to the formation of the Red Beds is at present unknown. 

 The area of marine conditions in Central Texas is to represent the Albany sea." 



EVIDENCE OF A BARRIER OR INTERRUPTION OF DEPOSITION OF RED BEDS TO THE WEST. 



There is some considerable probability in this suggestion, but the author, 

 traversing the region from Tucumcari to Las Vegas, New Mexico, in the 

 summer of 191 2, found no trace of red beds which could be referred to the 

 Permo-Carboniferous. The lowest red beds encountered yielded Phytosaur 

 remains and Unio, clear evidence of their Triassic age.'' 



" Case, Jour. Geol., vol. 22, No. 3, April-May 1914. In the paper cited the author gives details of the 

 stratigraphy of this region (see plates 11-13). 



