326 



BULLETIN OF THE 



be seen at the side of the railroad. The plane of the fault dips 45"" 



e^st; on the western side, the Upper Pentatncrua has a smooth, well- 

 rubbed wall ; on the east, the Catskill Shaly ends more unevenly, and 

 supplies a quantity of fragments for the two feet of fault-breccia. There 

 is no noticeable contortion of strata on either side. This example is 

 interesting as it m a violation of the so-called ''law of faults," (which I 

 believe is no law at all,) for the upthrow overlies the hade. In this 

 particular it confirms the hypothetical attitude of the fault-planes as 

 generally drawn in Appalachian sections by Lesley and others, although 

 these seldom if ever depend on* direct observation. The example is 

 further of use in showhig that the fault may result from the same com- 

 pressing force as the fold ; and not from horizontal tension, such as is 

 needed for the so-called normal fault. The throw here on the bank is 

 probably fifty or seventy feet ; it could be closely measured by more 

 leisurely observation. We succeeded in finding the apparent continua- 

 tion of the same fault half a mile to the north, but the intervening 

 details of the map need revision. On the next turn of the stream by 

 the railroad bridge, the upper limestones arc finely shown on the east 

 bank; on, the other side, an obscure fold or fault complicates their 

 succession. The grits and th(? thin Oriskany layer in the gorge at 

 Leeds have already been mentioned. 



A cross-fault probably determined the gap on which the Kaatcrskill 

 turns eastward from the Marccllus at the saw-mill ; for the folds do not 

 correspond on the two sides of the gap, and the vertical limestones of 

 West Berg seem displaced where they reappear on the north. 



Other points of interest are as follows, beginning at the north end of 

 the map: — Black Lake and a high hill next west of it; the hill is a 

 saddle of grits on a limestone anticlinal ; a rare occurrence. Canoe 

 Pond and the steep plunge of the limestone under it^ eastern side. A 

 Corniferous arch on either side of a little cross valley through which the 

 railroad passes south of Leeds. The Quarry Hill synclinal and the 

 Fuyk Valley anticlinal. The long tongue of Corniferous running down 

 to Van Luven*s Lake, and the large loose blocks of limestone at several 



r 



points along it. The southern anticlinal valley, and the narrow faulted 

 grit synclinals to the east of it. The way in which the several lime- 

 stones wrap around the disappearing ahticlinals is beautifully shown. 



Surface Geology. — Glaciated rock surfaces are very seldom seen 

 within the Little Mountain belt, but this is merely because the rocks 

 are generally too weak to hold them. The firmer sandstones of the 

 Hudson River group to the east show them abundantly, as on a large 



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