14 Geology, &fc. of the Connecticut. 



The veins traversing seinite are most frequently granite, 

 felspar being of a flesh colour. They are more numerous 

 in this than in any other rock, and are ofien intersected by 

 one another and by thin veins of epidote. The crossing of 

 these veins has produced many very interesting and singu- 

 lar displacements of portions of the rock. Where one 

 vein is cut off by the intersection of one that is newer, it 

 is not unfrequent to observe a lateral removal of the former 

 with the whole mass of the rock surrounding it, from one 

 to six inches. The vein itself, which is thus removed, is 

 rarely altered or injured. 



One of the most complete and curious cases of this kind 

 is exhibited in Fig. 6, It was sketched by the eye without 

 accurate admeasurement. A. B. C. is a triangular mass of 

 sienite; the sides of which are 6, 4, and 10 feet. A. B. is a 

 fissure in the rock : B. C. a vein of epidote and A C. the 

 line marking the lowest limit of the rock above the soil. 

 The whole rock is unbroken and as firmly united as any 

 rock of this character ever is. There appear originally 

 to have been two veins of granite traversing the rock in its 

 longest direction, the smallest an inch wide at one end and 

 widening towards the 'ither, and the longest 2 or 2 1-2 wide. 

 These have been cut through and strangely displaced by nn- 

 meroua veins of epidote crossing obliquely. 



a, «, a, and 5, 6, &, &;c. represent the granite veins as 

 displaced. 



d, d, d, he. represent the veins of epidote which are 

 rarely more than one quarter of an inch thick, and a few of 

 which are represented on the plate. 



c isa mass of gneiss or mica slate imbedded in the sienite 

 and crossed by the granite vein b. 



The locality of this rock will be described when we come 

 to speak of sienite. 



In those rocks that are stratified these veins make every 

 possible angle with the direction of the strata. And if I do 

 not mistake, the nearer they approach to the same direction 

 as the strata, the broader they become, and have a nearer 

 resemblance to beds. Sometimes they approach so near 

 the same course as the layers of the rock they traverse, 

 that it requires nice examination to determine whether they 

 deviate at all, A good example of this occurs in a locality 

 which many geologists have visited, and which many more 



