44 THE PERMO-CARBONIFEROUS RED BEDS OF 



gray to black, according to the amount of carbon. But over the larger portion of 

 the delta the iron of the soil is more or less completely oxidized during the season 

 of dryness, and the corresponding colors — yellow, orange, red, or brown — are in 

 evidence. The ratio of these oxidized and deoxidized sediments varies with the 

 flatness of the delta and the character of the cHmate." 



The conditions which permitted the deposition of the limonitic conglom- 

 erates did not long endure, for the beds are thin and there is a succeeding 

 thickness of loo or more feet of red clay, with beds of red and gray sandstones. 

 As shown above, the red deposits can only mean regions and periods where 

 and when large quantities of ferric oxide were poured into bodies of water, 

 either quiet or disturbed, and of considerable size. That the bodies of water 

 were frequently local in character, and disturbed by currents either due to 

 rivers or winds, is shown by the lack of continuity and the cross-bedded 

 condition. The variations in the strike of the beds, sufficiently large to be 

 followed for any distance, is extreme. For instance, south of Dundee the 

 strike of a shaly sandstone is almost at right angles to the prevailing north- 

 east-southwest strike of the limestone beds, which are the most continuous 

 beds in the region and must be regarded as indicating the dominant strike 

 in the region. Along the outcrop of this sandstone the author has found 

 many fossils of land and swamp reptiles as if they had been drifted to this 

 particular bar or beach by definite currents. Above this layer there is a 

 loose, coarse, almost arkosic sandstone, and above that a mass of coarse 

 conglomerate which I believe to be what Gordon interprets as formed of 

 previously wave-washed and wave-broken fragments of clay. If it has been 

 formed as Gordon thinks, the action must have been very local, for the bed 

 is not traceable for any great distance. (Plate 9, figs, i and 2.) 



There is a general suggestion in all the deposits of the Wichita of a 

 prevalent aridity; this comes from the highly oxidized condition of the 

 material, coupled with the lack of any quantity of vegetable remains. The 

 suggestion is borne out by the fact, noticeable throughout the series, of the 

 complete absence of any sulphides or other unoxidized or uncarbonated 

 minerals. The suggestion of local swamp or lagoon conditions given by the 

 presence of small quantities of blue or green clays and shales is more than 

 counterbalanced by the great preponderance of compounds high in oxygen, 

 by the absence of any black shales, and by the absence of any plant remains 

 other than a few impressions in the sandstones and clays. Moreover, I have 

 submitted some samples of the sand from these beds to Professor Sherzer, 

 of the Ypsilanti Normal College, who assures me that the grains have the 

 appearance presented by wind-blown sands. The frequent presence of copper 

 carbonate may point in a slightly different direction. Copper carbonate, as 

 azurite or malachite, frequently occurs in the form of nodules, or as coatings 

 upon fragments of petrified wood. It seems probable that the copper in the 

 waters (in what form we do not know) was reduced to the metallic state by 

 organic matter, and subsequently oxidized or carbonated. Thin veins of 



