62 H. D. Miser — Llanoria, the Paleozoic Land 



■ this paper he brought together and presented many facts 

 in support of his hypothesis that the Appalachians 

 formerly extended across the lower Mississippi Valley to 

 central Texas. Considerable information on the subject 

 was obtained by the late Dr. A. H. Purdue and the writer 

 during several years of study of the rock formations in 

 the Ouachita Mountains and Arkansas Valley, in Arkan- 

 sas, beginning in 1907. Xot only is this presented here 

 by the writer, but an attempt is made to bring together 

 and state briefly all the data that have been published by 

 other geologists. The writer is indebted to E. 0. Ulricli, 

 G. H. Girty, C. E. Siebenthal, Chas. Schuchert, and L. W! 

 Stephenson, who have kindly read this paper and offered 

 valuable suggestions. 



This paper consists largely of the presentation of 

 evidence for the existence of the old land area ; it does not 

 discuss more than the most striking events in its history. 

 Discussion of the complete history, which would be based 

 on the character and distribution of the rocks of the Gulf 

 Coastal Plain and the adjoining regions and on the 

 stratigraphic breaks presented by them, would be largely 

 hypothetical. 



The name Llano was applied to this old land area by 

 Bailey Willis- and has been used by Charles Schuchert^ 

 and E. 0. Ulrich,^ but the name Llanoria has been used 

 by E. T. Dumble^ and Sidney Powers.^ Of these two 

 names Llanoria is the more appropriate because Llano is 

 very frequently applied to the Central Mineral, or Llano- 

 Burnett, region of Texas, which was an outlier of the main 

 land area to the east, or which formed only a small part 

 of it if the two were connected. 



Since most of the present paper is a discussion of 

 numerous features found in the Ouachita Mountains and 

 Arkansas Valley, a brief summary of the geology of these 

 regions is given. 



^^ Willis, Bailey, A theory of eoiitinental structure applied to Xorth 

 America: Geol. Soc. America, Bull., vol. 18, pp. 394-395, 398, 1907. Dis- 

 coidal structure of the lithosphere, Geol. Soc. America, Bull., vol. 31, Plate 

 11 opposite p. 301, 1920. 



^ Schuchert, Charles, Paleogeography of North America, Geol. Soc. Amer- 

 ica, Bull., vol. 20, pp. 448, 457, 458, 470, pi. 49, 1910. 



The nature of Paleozoic crustal instability in eastern Xorth America, this 

 Journal, (4), vol. 50, pp. 403, 404, 407, 413,' 1920. 



* Ulrich, E. O., Eevision of the Paleozoic systems, Geol. Soc. America, Bull., 

 vol. 22, pp. 435, 476, 1911. 



^ Bumble, E. T., The geology of east Texas, Univ. of Texas Bull., Xo. 1869, 

 pp. 11-13, Feb., 1920. 



'^ Powers, Sidney, The Sabine Uplift, Louisiana, Amer. Assoc. Petroleum 

 Geologists, Bull., vol. 4, no. 2, p. 125, 1920. 



