REMARKS ON ULRICH'S COMMENTS 461 



In many cases the striations on tlie stones are surfaces of gliding in 

 the shales grazing the side of the erratics. Thus in figure 1 of plate 23, 

 the grooves and striae spring out from the air, so to speak, the upper 

 right-hand portion of the boulderet there shown having been covered at 

 the time of striation by shale, in which the continuation of the striation 

 must have taken place. The same characteristic is illustrated in the two 

 grooves crossing the protuberance in the middle of the pitted pebble 

 there shown. Indented pebbles of small size are common at Talihina 

 and may be seen at the end of striated grooves on the larger blocks in 

 a manner to show that the shoving of small pebbles past the larger stones 

 in the interstitial and other movements of the contorted shales was a 

 common method of producing the striae and grooves. Figure 1, plate 24, 

 shows one of these indented pebbles with a prominent groove or trail. 



The plastic appearance of the surface of the limestone spall, figure 2, 

 plate 24, shows how closeh^ the matrix was pressed to the contour of the 

 limestone, and the minute cleavage flakes of the limestone indicate that 

 the surficial layer of the limestone was like many slickensidos walls of 

 faults in a thin zone of flowage, resulting in an imbricated cleavage, a 

 feature unknown in the case of indurated rocks under glacial pressure. 



Lenticular beds of limestone breccia occur in the railway cut at Tali- 

 liina, and blocks of such beds occur weathered out on the surface. These 

 blocks are, of course, not transported erratics. The brecciation of the 

 limestone has apparently taken place in situ from crushing boulders and 

 drawing out the crushed and comminuted mass into bedded form. 



From the Choctaw fault, as shown on the State map of Oklahoma by 

 Doctor Gould, southward to Talihina in the railway cut, the Caney 

 shales are highly contorted and crushed. 



Floating Ice in the Caney Shale Sea 



As Mr. Tall' points out, it is ivasonablc to consider tlie boulders and 

 smaller stones as having been transported by some kind of ice action 

 from the nearest known exposure of the Ordovician limestones in the 

 Arbuckle Mountains. Floating ice is naturally suggested as the prob- 

 able agency, notwithstanding that to have pan-ice at sealevel demands a 

 greater degree of cold in this latitude than would be demanded for float- 

 ing detached portions of mountain or plateau glaciers entering the sea 

 in their zone of melting. 



The Caney shales are known to be marine from the occurrence of the 

 fossil shells in their basal portion, mentioned by Taff and described by 

 Girty. At no part of the section north of Talihina did I observe beds 

 resembling the tillite of typical Permian glacial formations. 



