248 CENTRAL MINERAL REGION OF TEXAS. 



knowledge of what properly constitutes a geologic division. With determina- 

 tions equally arbitrary, he classes all the granites as Azoic, but adds: 



Most, and probably all, of the granites of the Azoic region are of a later period than the 

 metamorphic rocks associated with them. 



Mr. A. R. Roessler, who had been engaged as draughtsman upon the Shu- 

 mard Survey, has published for himself and the Texas Immigration Bureau 

 maps purporting to give the boundaries of geologic systems. These were 

 well executed and fairly accurate for the time, hut they can hardly be re- 

 garded as of much original value, geologically. As mineral maps, so far as 

 they can be trusted, they have served a useful purpose. These were published 

 in 1875 and later. 



Buckley's second report,* written after a tour through the Central area, 

 adds little or nothing to our knowledge of the geology, although he again 

 generalizes rather freely upon the relations of his so-called Azoic and Lau- 

 rentian rocks to his Lower Silurian, but without giving any sections or de- 

 scribing any fossils. He mentions the occurrence of granite, with the Creta- 

 ceous directly superimposed, in Gillespie County, but refers to it as a general 

 mode of outcrop in that region, which is certainly not the case. 



Nothing of importance bearing on the geology of this region appeared in 

 print after 1876 until the year 1884, when Mr. C. D. Walcott, of the United 

 States Geological Survey, made a hasty trip into one of the most complicated 

 portions of the district, and published a brief resume of his conclusions, j- with 

 a cut showing a section of Packsaddle Mountain, as he interpreted it from 

 a partial view of the western flank. This paper is marred by two errors, as 

 yet uncorrected by the author. J This is not the place to discuss the con- 

 clusions announced, which are somewhat different from the views held by 

 previous observers, and which are rather broad generalizations from some- 

 what narrow observations in this area. Mr. Walcott concludes his article by 

 stating that 



The results obtained are: additional data on the Potsdam section and fauna; the Silurian 

 section and fauna; Carboniferous fauna; the geologic relations of what has long been known 

 as an Archaean area, and which is now referred to the Cambrian ; and the determination of 

 the age of the granite of Burnet County. 



*Second Annual Report of the G-eological and Agricultural Survey of Texas. By S. B. 

 Buckley, A. M., Ph. D., State Geologist. Houston, 1876. 



f Notes on Paleozoic Rocks of Central Texas. Amer. Jour. Sci. (3rd ser.), vol. XXVIII 

 Dec, 1884, pp. 431-433. 



\ One of these, in the section figured, is the drawing of the underlying rocks which he 

 calls the Llano group, as if they were dipping northward, instead of southward as he reports 

 in the text correctly. The other is the use of the word "Carboniferous" to designate the 

 upper rocks upon the summit of Packsaddle Mountain. This may be a misprint for "Cal- 

 ciferous," but there is nothing in the context to show it. 



