EXTENT OF FOLDING AND SUBSEQUENT EROSION 



465 



by this fact, but also on account of the 

 purity of the rock as a whole. It is well 

 cross-bedded, the bedding being of the 

 torrential, rarely the irregular type, and 

 it rests on an eroded surface of the Frank- 

 fort shale, with indications of old erosion 

 channels. On the south branch of Moyer 

 Creek, 3 miles southwest of Frankfort, 

 Herkimer County, the basal conglomerate 

 likewise rests on eroded Frankfort shale. 

 The entire series here is something over 

 100 feet thick (Hartnagel estimates it at 

 110 feet), 71 and the upper beds show re- 

 markably fine diagonal bedding (torren- 

 tial cross-bedding), the oblique layers be- 

 ing very long and followed by heavy hori- 

 zontal beds. It is interesting to note that 

 not only the coarseness, but also the thick- 

 ness of these terminal Lower Siluric (Ni- 

 agaran) elastics increases eastward. East 

 of Herkimer County, however, the Oneida 

 is generally absent, and the same is true 

 of the region north of the Mohawk, Upper 

 Siluric (Monroan) strata resting directly 

 on the Ordovicics in the northern Helder- 

 bergs. 



The Tuscarora. — Southward along the 

 Appalachian front we do not meet with 

 these strata again until we come to the 

 Susquehanna Gap through Blue Moun- 

 tain. Here the contact with the Hudson 

 beds is not shown, but from the general' 

 relationship of the dip there may well be 

 an unconformity here. The following 

 section (figure 10), transcribed Prom my 

 note-book, shows the relation of the strata. 

 The Hudson beds of argillaceous sand- 

 stones and shales dip gently to the west, 

 while the Siluric beds are overturned io 



7L null. 107, N. Y. State Museum, p. 29, pis. i and li. 

 XXXII— Bull. Geol. Soc. Am., Vol. 24, 1912 



