488 



Scientific Geology. 



quent date, crossing them nearly at right angles. Here then we 

 have granite of three distinct epochs. 



No. 25 shows us granite of four successive epochs of eruption. It 

 is the sketch of a bowlder, 20 feet long and 10 feet thick, lying in 

 West Hampton. The great mass of the rock belongs to the first 

 epoch. The vein a, a, a, was produced at the second epoch. This 

 was intersected by b, at a third or subsequent epoch. This, as well 

 as a, were intersected by the vein c (and probably at the same time by 

 d,) at a fourth epoch. The lateral removal of the middle portion of 

 the vein a, seems to have resulted from the intrusion of the veins b 

 and c, whereby the wedge shaped portion of the rock between them 

 was crowded out of its place. 



I have heretofore described and sketched a case in which a rock of 

 sienite (sienitic granite,) contains granite veins of three subsequent 

 epochs. The case now described corresponds to that, except that the 

 base of the one sketched below, is genuine granite. Both of them, 

 however, may be regarded as presenting us with granite erupted at 

 four successive epochs : and this is the greatest number that I have 

 ever met with. 



(25) Granite Veins in Granite ; W. Hampton. 



The next case is one of no peculiar interest, hardly worth preser- 

 ving indeed. The sketch shows a vein of coarse granite, 10 inches 

 wide, traversing a mass of finer granite, and cutting off and remov- 

 ing laterally another vein of coarse granite, 2 1-2 inches wide. It oc- 

 curs in Southampton, not far from the spot where an adit has been 

 made in the granite to reach a vein of galena. 



