78 NEW YORK STATE MUSEUM 



moderate swells the older masses have not been exposed, except 

 where faulted. Much of the surface rock may be of Beekmantown 

 or Upper Cambric age, the latter belonging to the upper dolomitic 

 layers of the sediments of that epoch. 



Structural features. The hiatus that is present between the 

 Beekmantown and the Trenton within the Wappinger creek belt has 

 its counterpart along the western margin of this limestone; but the 

 failure to find any conglomerate farther east, such as usually repre- 

 sents the base of the Trenton, not only in the Wappinger creek belt 

 and along the western margin, but also in the slates at ithe north, 

 leaves much uncertainty as to the relative stratigraphic position of 

 much of this Fishkill limestone. The presence of certain faults adds 

 to the perplexity ; while the general faulted position of the Fishkill 

 limestone as a whole and the absence of the slates within it rather 

 leaves the impression that it is made up chiefly of limestones older 

 than the Trenton conglomerate, except where younger beds have 

 been faulted in. 



In spite of faults and thrusts the general folded arrangement of 

 the Fishkill limestones can in some instances be made out with a 

 fair degree of exactness. 



In the hamlet of W'olcottville the limestone is in contact with the 

 gneiss. In the town of Alatteawan it first rests against the slates, 

 which are almost certainly younger, and then on the gneiss, then on 

 the quartzite and finally on the gneiss again. The quartzite contact 

 may be normal. The gneiss contact may also be normal in places, 

 but in such cases the gneiss is presumably the equivalent of the 

 basal quartzite and represents an altered condition of the gneiss. 



The fault on the west of the Glenham belt represents an early 

 thrust which was succeeded and outstripped by the Bald hill thrust. 

 The western break also bounds the IMatteawan inliers at the west. 

 Faults bound the Glenliam belt on the south and the northern inlier 

 of Matteawan on the north and between these the slates have 

 apparently been dropped. 



Numerous breaks may occur in Matteawan so that the limestone 

 resting on the quartzite in that town may not be of the same age as 

 that which rests against the slates. The limestone is traceable to the 

 north across Fishkill creek and through Glenham and be3'Ond. But 

 as a rule not much can be made out about the structure. 



At Wilsey's quarry on the Fishkill-Glenham road the arenaceous 

 limestone strikes n. 35° e. and dips about 51° s.e. In the field just 

 north the fossiliferous Beekmantown and interbedded limestones 

 have a strike varying from n, 15° w. to n. s. and a dip of 35° e. One- 



