THE PLAINS PROVINCE 



101 



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 want- 

 ing, as does the fauna, north of the Texas line; the only exceptions noted were 

 Fusidina 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 con- 

 stituted 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 disturbances 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 conditions east of the 

 Guadalupes. If such were the case, we would expect the Guadalupian 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. 3] indicates the probable relationship of the 

 marine areas during the 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 condi- 

 tions and the lines alternating 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." 



This position has been contested by Girty, as is shown below (page 144), 

 and the difificulty of such a correlation is quickly apparent when the relation 

 of the Pecos beds to the Delaware and Capitan limestone is understood. 

 As has been shown by Richardson and others, the Castile gypsum and the 

 Rustler limestone lie beneath the red beds of the Pecos Valley, and there is 

 every reason to believe that these are equivalent to the uppermost red beds 

 of Texas or the Triassic red beds; probably both are represented in the better 



