268 M. L Goldman — Catahoula Sandstone of Texas. 



geographic conditions under which the sediments were formed, 

 to permit of direct matching of diagrams. But certain general 

 factors and conditions can be distinguished. The principal 

 features of the diagrams are the degree of the sizing, i. e., the 

 extent to which a single size has been concentrated forming 

 the maximum in the diagram ; the relation of the amount of the 

 other sizes to this maximum or, as Mohr calls it, the " curve " 

 on each side of the maximum ; and the size which forms the 

 maximum. It must be noted, however, that even simple com- 

 parisons are made difficult by the differences in the limits of 

 sizing used by different workers. 



Mere inspection shows at once that the closest affinities of 

 the Catahoula sandstone are with seolian and beach sands. 

 Certainly neither Mohr's diagrams of stream deposits (i. e. 

 stream flood-plain deposits) (fig. 12), nor the lagoonal 

 sediments (figs. 10 and 11), nor the sediment off the Rhone 

 delta (fig. 9) show as good sizing. 



In the two analyses of beach sands given by Mohr, one of 

 which is represented in fig. 2, 90 per cent and 98 per cent re- 

 spectively of the samples is coarser than J mm , the big maximum 

 being between \ and J mm . Oldham's analysis of beach sand 

 (fig. 3), however, shows much less perfect sizing, but the exact 

 conditions for his material are not known and the diagram 

 strongly suggests weathering (see below). 



Turning to dune sands, we find that the analyses to which 

 references have been given practically all agree in indicating 



cussion of aBolian sands with full bibliography, from which some of the 

 following references are taken.] 



Udden, J. A.: The mechanical composition of wind deposits. Angustana 

 Library Publ. No. 1, Rock Island, 111., 1898, especially diagrams, pp. 13-23, 

 and summary, p. 61. [Fig. 5, see p. 23, table 14.] 



Thoulet, J. : Etude mineralogique d'un sable du Sahara. Bull. Soc. Min. 

 Fr., iv, pp. 262-268, 1881. [Fig. 6, see p. 263.] 



Sabban, P.: Die Diinen der sud-westlichen Heide Mecklenburgs. Mitt. 

 Grosherz. Meckl. Geol. Landesanstalt, viii, pp. 1-49, 1897. 



Lehmann, Paul : Wanderungen u. Studien in Deutschlands grossten 

 binnenlandischen Diinengebiet [Posen]. Jahrb. Geog. Ges. Greifswald, x, 

 pp. 351-379. 1905. 



Atterberg, A.: Die rationelle Klassifikation der Sande u. Kiese. Chemztg., 

 xxix, No. 15, pp. 194-198, 1905. Uber die Korngrosse der Dtinensande. Do. 

 Do. No. 80, p. 1074. 



Keilhack, K.: Einige Bemerkungen ti. die Korngrosse der Dtinensande. 

 Chemztg., xxix, No. 53, p. 723, 1905. 



Thoulet, J.: Etude bathylithologique des cotes du Golfe du Lion. Annales 

 de Tlnst. Oceanogr., Monaco, iv, fasc. 6, 1912. [ Fi £- 8 > see P- 53 '■> fi S- 9 > 

 see p. 55.] 



Sudry, L. : L'Etang de Thau. Annales de l'lnst. Oceanogr, Monaco, i, fasc. 

 10. 1910. [Fig. 10, see p. 44 ; fig. 11, see p. 112.] 



Sorby, H. C. : On the application of quantitative methods to the study of 

 the structure and history of rocks. Quart. Jour. Geol. Soc, lxiv, pp. 185- 

 186, 1908. 



Sudry, L.: Experiences sur la puissance de transport des courants d'eau et 

 des courants d'air, etc. Annales de l'lnst. Oceanogr., Monaco, IV, fasc. 4, 

 1912, especially p. 67. 



