92 ENVIRONMENT OF VERTEBRATE LIFE, ETC. 



"One of the most interesting features of this whole region is the nature of 

 the changes from the light-colored limestones and shales to the dark-red sand- 

 stones and peculiar shales of the Red Beds. 



"The shales are red much farther north, as a rule, than are the limestones 

 and sandstones. The change in color is frequently accompanied by some change 

 in the character of the shale. The red shales are usually much less compact 

 and durable and in the immediate region covered by this report seem to become 

 more or less charged with very fine sand. On account of the fact that the shales 

 are usually hidden from view, the nature of the transition has not been observed 

 so carefully as has the transition from limestone to sandstone. 



"In the case of some of the higher limestones, Wreford, Fort Riley, etc., 

 sand appears in the limestones, which have usually thinned appreciably. The 

 sand may gradually increase for considerable distances, say from a few rods to 

 a few miles, and become first a sandy limestone, then a calcareous sandstone. 

 Followed still farther, the traces of calcium carbonate disappear, sometimes to 

 reappear as limestone in some areas. Again, as is shown along the Shawnee 

 branch of the Santa Fe Railroad from Kaw City to Skedee, or the upper Wreford 

 limestone at Hardy, the first traces of the transition are seen in purple blotches 

 scattered through the stone. These may enlarge and increase in number until 

 the whole stratum is practically a purple or red limestone. In other regions the 

 limestone may turn almost scarlet in a rod or two, as in the case with a lime- 

 stone in the escarpment south of Gushing. The red limestones of the latter class 

 usually dissipate quickly into sandstones. They are usually fossiliferous. 



"Sometimes a limestone layer will grade into a sandstone layer and then 

 change back again into limestone in a few rods. Indeed, this is not infrequent in 

 the region between Kaw City and Pawnee, and west and northwest of Pawnee. 

 * * * Sometimes these sandstone replacements may not be more than 3 or 4 

 rods across. * * * The sandstone in such cases is usually calcareous, but in 

 some instances it is not. 



"At one point a ledge was made up of sandstone and limestone in indis- 

 criminate masses, which were very irregular in form. The masses were all rather 

 small, hardly ever over 2 feet in diameter and ranging from that to mere pockets. 

 Sometimes there were pockets of sandstone in the limestone and sometimes 

 pockets of limestone in the sandstone. That is, sometimes one or the other forms 

 the predominating rock. On the whole, the exposure was largely limestone. 

 In most all cases the transition from the light-colored sandstone to red sandstone 

 takes place before going a great distance. * * * 



"After passing some distance south or southwest of the region of transition 

 just described, in which the sandstones maintain their usual thickness and relative 

 positions, we pass into another zone where they thicken and thin, pinch out, end, 

 and even cut out intervening beds of shale and limestone. * * * In this region 

 stratigraphic work becomes more uncertain, the fossils are wanting, and there 

 seems to be no character of the rocks to tie to. At the bridge at Ripley is a 

 sandstone about 40 feet in thickness which elsewhere is usually about 4 or 5 feet. 

 All the sandstones of the section at Vinco are thicker than the average, but appear 

 to pinch out on the south side of the river between Vinco and Goodnight, so far 

 as it is possible to determine by surface exposures. At Goodnight they have 

 more than normal thickness. These belts of thickened sandstones extend nearly 

 north and south, with the region of very thin sandstones or mere traces of white 

 sand and iron concretions marking their horizons between them. 



