12 NEW YORK STATE MUSEUM 



west of the sandstone) exhibits overthrusting to the west, evi- 

 dently a movement of ancient date for there is no observable 

 displacement at the top of the quarry just north of the Brothers' 

 Institution. The contortion and crushing of the sandstone is 

 either' of Posthudson or Appalachian date, presumably the 

 former. The situation of the postglacial faults along the eastern 

 border of the sandstone core of the overturned syncline, in the 

 plane of the reversed dip of the stratification, is precisely where 

 overthrust planes would be expected to arise in mountain building 

 from a continuation of the ancient pressure. If this view be cor- 

 rect, it is to be expected that these thrusts would find expression 

 elsewhere in the overturned limbs of anticlines and synclines. As 

 the folds die out north and south, so should the faults die out 

 north and south. 



In the quarry south of the Brothers' Institution in the same 

 sandstone core at the east end of Trenton street, there were no 

 exposures of the glaciated surface at the time of my visit and no 

 postglacial faults were seen. 



Relation of faults to landslides in Troy. Of all the cities and 

 towns along the banks of the Hudson gorge, Troy appears to 

 have suffered most from the slipping of the glacial and post- 

 glacial clays. These landslides are recorded in the literature of 

 the State. Thus on March 17th, 1859, St Peter's College lost 

 3, building in process of erection by a landslip.^ 



It is a noticeable fact that many of the older brick buildings 

 in various parts of Troy exhibit cracked and displaced walls. 

 A cursory examination of the city made with reference to the 

 possible occurrence of faults in the bed rock underlying the 

 place since the construction of houses showed a considerable 

 number of buildings upon the terrace below the eastern wall of 

 the Hudson river gorge in which there was a fracturing of the 

 brickwork and a drop of the western part of the building or the 

 relative uplift of the eastern part of the house precisely in the 

 manner in which the rock surface south of the Poesten kill has 

 been dislocated. The following examples taken from my notes 

 illustrate the above statement and the exceptions to it. 



A foundry in South Troy shows an uplift on the western end 

 of the building accompanied by a displacement, traceable through 

 three stories, which has been in part repaired. This is the most 

 noticeable movement of the kind observed. 



^French, J. H. Gazetteer of the State of New York. Syracuse, N. Y. i860, p. 560, footnote. 



