488 NEW YORK STATE MUSEUM * 



be two sets of joints with this strike, a set of dip joints, dipping 

 with the foliation which is to the south in general, and another set 

 at right angles dipping north [see pi. 4]. These would seem quite 

 certainly to be compression joints whose location was influenced by 

 the foliation, but whether they antedate the vertical joints or 

 not can not be told. 



Lines of excessive jointing are not infrequent in the eruptives. 

 In such places from two to four joint sets are well marked, and 

 the joints are closely spaced, their distance apart being measured 

 in inches rather than feet, chopping up the rock into a multitude 

 of small blocks, and forming prominent lines of weakness in it. 

 Often multiple faulting has taken place along these strips on one 

 of the joint sets, grinding and slickensiding the rock surfaces. This 

 faulting seems to be of Precambric age, and has been noted in sev- 

 eral places, affecting both- the eruptives and the gneisses. The 

 entire rock complex along the gorge at Raquette falls (gabbroid 

 anorthosite cut by gabbro) is remarkably shattered by multiple 

 jointing of this sort throughout the length of the gorge, a distance 

 of nearly 1 mile. At the lower end the sheared joints run n. io° e., 

 but elsewhere the trend is n. 4o°-5o° e., and no n. io° e. joints 

 appear. The trend of the gorge is clearly determined throughout 

 by this joint set. There are also two sets of inclined joints, strik- 

 ing n. 50 w., one hading 20 n., the other 45 s. It is exceedingly 

 probable that considerable faulting has taken place on the north- 

 east joints. 



Many excellent examples of the same sort are shown in the fine 

 series of exposures along the roads in Litchfield park in the 

 granites and granitic syenites. "By the road along the north shore 

 of Duck lake, about midway of the lake, occurs the most shattered 

 material seen in the quadrangle. The rock is granitic syenite, cut 

 by Morris granite. The slipping has been along a n. 65 e. joint set, 

 so closely spaced as to form an excellent fracture cleavage, con- 

 siderable secondary quartz has been deposited, and the rock rap- 

 idly weathers down to a mass of fine splinters, strongly resem- 

 bling rotted wood splinters at a little distance, all due to" excessive 

 shattering, accompanied in all probability by faulting. 



Faults. It is not easy to demonstrate the presence of faults in 

 districts whose stratigraphy has not been deciphered and to defi- 

 nitely locate them and determine their magnitude, in such areas, is 

 well nigh impossible. It is however known that faults are fre- 



