INTRODUCTION. 247 



formation, probably the same as described by Dr. Rcemer as Lingula acutangula; * * * 

 also fragments of others, perhaps L. prima (Con.?) 



Near Blufftown, about three miles north on Beaver Creek, in Burnet County, we obtained 

 some specimens of Trilobites. They showed in great numbers in the limestone of this locality. 

 Comp. Rcemer, Kreidebildungen V. Texas, 1852, p. 7; and also Owen's Report of the Geo- 

 logical Survey of Wisconsin, Iowa, and Minnesota, 1852, Tab. I. A., Fig. 18. 



Following Mr. Glenn's resignation, Dr. S. B. Buckley became State Geol- 

 ogist, by appointment, early in 1874. The same year he published his first 

 report,* which was largely a copy of his preliminary report of 1866, with 

 amplifications. On page 72, of this last report, under the head of " Devo- 

 nian," he remarks: 



In 1860, when engaged with Dr. Shumard in the survey of San Saba County, some of 

 the limestones and shales in the eastern part of that county and the northwestern part of 

 Burnet were referred by him to the Devonian. The Trenton [sic] limestone was the forma- 

 tion recognized; f its chief fossils found were of the following genera: Bellerophon, very 

 common, Maclurea, Orthis, Murchisonia, Pleurotomaria, and some other genera peculiar to 

 that period. Since then I have not revisted that portion of these counties, the whole of 

 which needs re-examination. 



Referring to the Lower Silurian, Buckley, in this report of 1874, recog- 

 nizes "the calciferous sandrock, magnesian limestone, and Potsdam sand- 

 stone." He gives more details of rocks and fossils, but nothing which had 

 not already been announced by Dr. B. F. Shumard. He, however, attempts 

 a closer classification, and is the first writer who designates any particular 

 portion of the strata of our area by the name of Laurentian. He remarks: J 



Beneath the Potsdam, which rests unconformably upon it, is a dark blue shale in strata, 

 upraised at various angles, large and small; lithologically it resembles some of the old 

 slates of Vermont and New Hampshire, and also of the mountains of North Carolina, in the 

 granite regions of those States. No fossils have been found in these Texas shales. In the 

 bed and banks of Honey Creek, near the base of Packsaddle Mountain, it is an. argillite or 

 roofing slate, with two cleavage directions. 



About four miles west of the town of Llano, in the bed of a stream, these two cleavages 

 are well shown in the uptilted strata, extending from bank to bank, and the slate is changed 

 into a light grey mica slate. All the gradations of such changes can be seen in Llano County, 

 sometimes the slate being changed into a gneissoid rock with the vertical cleavages distinctly 

 placed, forming large slabs. Friable mica slates, containing garnets, sometimes underlie the 

 granite. 



This description to one familiar with the region must appear extremely 

 crude, and it demonstrates clearly enough the fact its author had no adequate 



* First Annual Report of the Geological and Agricultural Survey of Texas. By S. B. 

 Buckley, A. M., Ph. D., State Geologist. Houston, 1874. 



f Upon the margin of p. 72, in a copy supposed to have been corrected by Mr. Buckley, 

 this sentence has been changed to read "The Hamilton group was recognized; its chief 

 fossils," etc. 



%Loc. cit, p. 76. 



