680 ABSTRACTS OF PAPERS 



but a relation of this sort is usual in conformable sequences where a coarse 

 sediment has been deposited on fine-grained material. Now that Doctor Greg- 

 ory has established the presence of an unconformity by finding overlaps in the 

 region to the north, it appears that this must be the relation also in the area 

 near the railroad. 



It appears to me that the coarse deposits of the Shinarump are in broad, 

 irregular zones which represent the channels of streams that flowed in various 

 directions over the surface, probably mainly during times of freshets. 



FURTHER DISCOVERIES IN THE TACONIC MOUNTAINS 



BY ARTHUR KEITH 



{Abstract) 



A paper presented by the author to the Society at its last meeting described 

 the various limestones which sweep around the slate mass forming the north 

 end of the Taconic Mountains in Vermont. During this fall further work by 

 the author on the slates of the mountains supports the conclusion stated last 

 year, that the contact of the limestone and slate is a fault contact, with the 

 limestones (Stockbridge) lying under the slates. 



By detailed work the slates have been mapped and subdivided into seven 

 formations, five of which are at some point in contact with the limestone. 

 These formations are in brief: (1) at the top green, greenish gray and whitish 

 gray slate; (2) massive, vitreous white quartzite ; (3) greenish gray slate, 

 witb thin seams and beds of green quartzite and cherty quartzite: (4) black 

 slate; (5) calcareous, ferruginous quartzite; (6) blue slate, with blue lime- 

 stone lentils; (7) gray slate, with thin gray or whitish quartzite seams and 

 layers. At the west side of the Taconic Mountains the argillaceous beds are 

 slates, but become phyllites or fine schists at tbe east by increase of metamor- 

 phism. This is most seen in the top and bottom formations and least in the 

 black slate, ferruginous quartzite. and limestone. Lower Cambrian fossils are 

 found in the limestone lentils of the blue slate, while the ferruginous quartzite 

 bas always been recognized as characteristic of tbe Cambrian. All these for- 

 mations, including tbe known and characteristic Cambrian horizons, pass 

 through dozens of pitching folds, entirely across the north end of the Taconic 

 Mountains from west to east. 



Inasmuch as the divisions of the Ordovician Stockbridge limestone in this 

 area dip under the slates known to be Cambrian and these in turn dip and 

 pitch away from the limestones, and inasmuch as the limestones and slates are 

 all unconformable witb tbe general contact, an overthrust of the slates seems 

 the only competent explanation of their relations. 



PRELIMINARY GEOLOGICAL MAP OF THE NAVAJO-MOKI RESERVATION 

 BY HERBERT E. GREGORY 



(Abstract) 



Reconnaissance in northeast Arizona and southeast Utah sbows a wide- 

 spread distribution of the Permian. Triassic, Jurassic, Cretaceous, and Tertiary 

 strata, previously known to occur in southwestern Colorado. Volcanic necks, 

 dikes, and remnants of lava flows aTre distributed throughout the area. 



