92 NEW YORK STATE MUSEUM 



the extent to which this basal series is represented. Along the 

 western margin of the Fishkill limestone, as shown east of the 

 Glenham belt, the conglomerate has plainly been eroded so exten- 

 sively that no idea of its original thickness can be gained. At 

 Swartoutville the conglomerate is apparently thin and passes 

 quickly into a series of interbedded bluish limestones and gray limy 

 shales. The impure shaly limestones along the railroad track west 

 of Hopewell Junction, at the apex of the limestone angle and those 

 near Arthur sburg station, are probably near the base of the slate 

 formation. At Arthursburg the conglomerate is present at a dis- 

 tance of a few hundred yards from the shaly limestones at the 

 station. In the localities east of Pleasant Valley, which have been 

 described, the conglomerate is interbedded with and followed by 

 calcareous quartzite, the blue fossiliferous mud rock not being 

 present. 



At the east within this quadrangle the rocks associated with the 

 conglomerate, though varying in texture from shaly rocks to 

 quartzitic ones, tend to be more silicious than those farther west. 

 Folding and faulting have doubtless brought the two into their 

 present rather close proximity. 



Other varieties within the slates. This formation shows many 

 varieties of more or less altered clastic rocks, ranging from muds to 

 fairly coarse conglomerates. While folding and faulting have pro- 

 duced the greatest confusion, it seems possible to make out the 

 general sequence. The writer's observations favor the idea that the 

 calcareous conglomerate and overlying quartzitic limestone represent 

 an eastwardly overlapping sea. These were quickly followed in 

 some cases by limy mud rocks and in others by argillaceous cues. 

 These were both succeeded by a clastic series of both argillaceous 

 and calcareous nature with one and sometimes the other element 

 in excess and occasionally with so much lime as to form an impure 

 lime rock. The varieties varied in texture and followed each other 

 irregularly. Impure argillaceous muds predominate, and are inter- 

 bedded with limy muds and grits of varying thickness, but often 

 attaining several feet. Grits often reaching conglomeratic texture 

 are frequent. In these, the larger particles range from the size of a 

 pin head through that of a pea to that of a walnut and larger. 



On the whole, the finer-textured members are more characteristic 

 of the basal portions of the series and the coarser and gritty layers 

 of a higher horizon. Such a series as has just been described is 

 folded in between the red slates of Matteawan and those south of 

 the clay pits at Paye's brickyard, and the members are exposed at 



