276 CENTRAL MINERAL REGION OF TEXAS. 



from their apparently greater development in some localities than others, but 

 the statement is by no means strongly supported by past observations. 



II. EPARCHY AN GROUP. 



There is less apparent propriety in placing the next succeeding system in a 

 different group from the Fernandan than there is in separating the former 

 from the overlying systems by a profound distinction. Structurally speak- 

 ing, the affinities of the strata above the Click series are much nearer the 

 Archaean than the Cambrian. Lithologically, there is perhaps quite as great 

 a divergence upon one side as the other, but the impression made upon the 

 student in the field must certainly be more in favor of an Archaic reference. 

 In the absence of fossils one is also left in doubt whether to regard the beds 

 as belonging to a Pre-Paleozoic Post- Archaean group, or to consider them as 

 an independent group above the Archaean. There seems to be no doubt that 

 most modern geologists would rule them out of the Paleozoic. 



Probably the best assignment for the present is to the Eparchaean Group 

 of the United States geologists. Only one system has .been recognized in 

 these Pre-Cambrian rocks, for which I propose the name Texan, as the pro- 

 visional equivalent probably of the whole of "Walcott's Algonkian System. 



3. THE TEXAN (ALGONKIAN?) SYSTEM. 

 As remarked before, Mr. Walcott first gave the county name of Llano to 

 a set of " alternating beds of shale, sandy shales, sandstone, limestone, and 

 schists " in the Honey Creek Valley, " that strike east and west, dipping south 

 15 degrees to 40 degrees." Wherever he met any of these rocks he seems 

 to have found their general strike to be latitudinal. Such evidences to the 

 contrary as he must have seen " across the valley of Honey Creek" in going 

 "four miles west of Packsaddle Mountain," he has explained by stating that 

 there "the strata of the Llano group have been more metamorphosed, pli- 

 cated, and broken by intrusive dykes of granite."* The further facts that he 

 found Cambrian sandstone resting upon granite on Morgan Creek, in Burnet 

 County, and upon his Llano strata at Packsaddle Mountain, were accepted as 

 conclusive evidence of the Pre-Potsdam age of the granites of the region. 

 It would probably have been impossible to unravel the history of this com- 

 plex area without wider knowledge than could be gleaned in the time at his 

 disposal; but his choice of field was peculiarly unfortunate, because it led 

 him into errors which might have been avoided by the examination of a 

 limited encircling area. The district between Packsaddle Mountain and the 

 Riley Mountains is one in which the true trend of the Texan system, includ- 



*Paleozoic Rocks of Central Texas. American Journal of Science (3d ser.), vol, XXVIII, 

 1884, p. 431. 



