M. I. Goldman — Catahoula Sandstone of Texas. 283 



show an arrangement of their long axes parallel to the bottom 

 and tranverse to the direction of current or wave motion. 

 Only a violent current carrying masses of sand would seem 

 capable of burying them in such chaotic condition, and I ques- 

 tion whether such a current would allow these relatively light 

 fruits to settle at all. 



But the material as described macroscopically was not all 

 of this massive type with random orientation of the plant 

 fossils. The parallel arrangement of leaves in others of the 

 specimens may be regarded as a kind of bedding or lamination 

 of the including sand. This arrangement of leaves, as just 

 explained iu the discussion of the other type of occurrence, 

 can, I believe, arise only under water. Furthermore the 

 accumulation of the leaves in masses with general parallelism 

 of the individual leaves suggests quiet water, at least absence 

 of violent currents. At the same time the fact, noted in the 

 macroscopic description, that even these leaves are not perfectly 

 flat and parallel, suggests rapid accumulation of the enclosing 

 sand. The same conclusion is suggested by the bunching 

 of the leaves in a mass yet with sand between most of the 

 individual ones, for the bunching indicates that they accumu- 

 lated rapidly, yet the sand kept pace well enough to form 

 thin films between many of them. If then the sand was 

 accumulated rapidly and yet the water was moderately 

 quiet, there is some suggestion that it was not the water that 

 carried this pretty coarse sand but rather that the sand was 

 brought in from the outside — that is by wind. However, in 

 the absence of observational data on the burial of leaves in 

 sands this conclusion too is very hypothetical. 



10. Clay Galls. 



General character. — The last macroscopic character to be 

 considered is the occurrence of a fine, whitish, pulverulent 

 substance partly as matrix of the sandstone but more especially 

 as small lumps up to about \ inch diameter. These lumps or 

 " clay galls " are especially abundant in the specimens with the 

 masses of flat leaves. 



Lumps and granules of this kind are found in regions of 

 dunes, in river flood planes where sand blows about, on 

 the desert shore of the Red Sea,* etc. f They originate 

 by the drying out of a deposit of clay resulting in the forma- 

 tion of larger or smaller flakes which are picked up by wind 

 or water to be buried in the midst of sands. Enough fine 

 material is present, even in dune sand, to form thin deposits of 

 this kind when the dunes are washed by rains. It settles in 

 the hollows between dunes, where it soon dries out to be 



* Walther, J.: Einleitung in die Geologie, III, p. 847, 1893-4. 

 fGrabau, A. W.: Principles of stratigraphy, pp. 564, 711, 1913. 



