M. I. Goldman — Catahoula Sandstone of Texas. 267 



Species of heavy minerals present and their relative 

 amounts. — The species of heavy minerals recognized were : 



Magnetite : It is safe to estimate that this mineral is at least 

 half of the heavy minerals present, but a further quantitative 

 separation did not appear feasible or necessary. 



Zircon : This mineral appeared nearly as abundant as 

 magnetite so that the two together are the essential heavy 

 minerals present. The zircon shows all conditions of wear 

 from brilliantly fresh crystals to well-rounded grains. There 

 are many variations of color, green, typical smoky hyacinth, 

 and colorless. 



The other minerals recognized, all scarce, were : Cyanite, 

 corundum, epidote, tourmaline, muscovite, andalusite, biotite 

 (1 grain), staurolite (1 grain), pleonaste (?j (dark blue green, 

 isotropic, 1 grain), pyroxene, glauconite (?) (an ochrous 

 botryoidal grain), many limonitic grains, and several other 

 dirty colored opaque varieties of grains.* 



II. Interpretation. 



What evidence does eacli of the above facts give as to the 

 conditions of origin of the Catahoula sandstone ? 



1 . Sizing. 



In the accompanying figures (figs. 1-12) I havef pre- 

 sented in the form of diagrams the results of mechanical 

 analyses of some types of sediments.;); These analyses are as 

 yet too meager, and not sufficiently correlated with the exact 



*As it seemed possible, especially from the very unusual fact that the 

 tourmaline was strongly cori'oded, that the KOH had destroyed some of the 

 minerals originally present, a separation was also made on a quantity of 

 ''very fine" sand obtained by crushing. It yielded tourmaline perhaps a 

 little more abundant and above all in good fresh prismatic form, showing 

 that the KOH had acted on this mineral. A grain or two of rutile was also 

 observed, but this mineral may merely have been missed in the sample 

 obtained by decomposition. Otherwise no difference was noticed between 

 the mineral contents of the crushed and of the decomposed sample. 



f Where dimensions in the original analysis are not given in fractions, I 

 have placed two rows of figures under the diagram. The upper row are 

 those given by the author ; the lower are the same rounded off in the nearest 

 fractions that will permit ready comparison of different diagrams. For 

 ready comparison I have also rounded off and combined quantities slightly 

 in some of the diagrams. 



JFor quantitative results of mechanical analysis including the analyses 

 reproduced in the diagrams of this paper, p. 269, see the following : 



Mohr, E. C. Jul.: Ergebnisse mechanischer Analysen tropischer Boden. 

 Bull, du Depart, de l'Agric. aux Indes. Neerlandaises No. 47 Buitenzorg, 

 1911. [Fig. 2, see p. 42 ; fig. 4, see p. 43 ; fig. 12, see p. 37.] 



Oldham, R. D.: Note on the sandhills of Clifton near Karachi. Mem. 

 G. S. Iud., xxxiv, pt. 3, pp.* 148-150, 1903. [Figs. 3 and 7, see p. 150.] 



Free, E. E. and S. C. Stuntz : The movement of soil material by the wind. 

 U. S. Dept. Agric, Bureau of Soils, Bull. 68, pp. 68-70, 1911. [Short dis- 



