' On the Betations of Granite. ' 409 



that, whatever their size might be, the position of their strata or lamiiiBB 

 was the same as that which the strata of the same roct held when at 

 equal distances from the granite. Localities being mentioned where these 

 phenomena were well exhibited, Mr Cunningham stated, that he wonld 

 now review another class of granite masses, and which, he said, might per- 

 haps be denominated " imbedded granite veins," from the circumstance^ 

 1st, that these occur as layers alternating with strata, but thinning out at 

 both extremities ; 2d, as masses crossing strata at all angles ; 3d, as 

 masses in some parts of their extent running parallel with the strata, and 

 also crossing them ; while, 4thly, they form bodies of circular or ellip- 

 tical shapes, which, in some instances, are contained within 07ie stratum, 

 while in others they are inclosed among several. Farther, it was affirm- 

 ed that all the forms of these imbedded granite masses, emitted^ as trae 

 veins do into strata, numerous small branches, which never change the 

 position of the strata in which they occur, or of their laminse, and also 

 that if masses of the strata occurred imbedded in these concretions, that 

 such included portions had a laminar arrangement of the same position 

 as that which was held by the adjoining strata, it mattered not whether 

 that were rectilinear or convoluted. Jlr Cunningham also observed, that 

 these imbedded granite masses varied in shape to a great extent, that 

 one might exist as a layer for many 100 feet, and at last swell out 

 into a most irregularly round shaped body, which might perhaps send 

 out another small ramification, again to finish in another large mass. In 

 aze, the imbedded granite concretions were said to be from that perhaps 

 in which a granite concretion might be produced by the aggregations of 

 a few crystals, to one of an immense magnitude. In regard to the rela- 

 tions of the smallest concretions to strata, it was stated that these were 

 the same as those of the largest, inasmuch as they never disturbed the 

 laminse in which they occurred, and, in conclusion, it was mentioned that 

 the only diflerencc which existed between a minute granite concretion and 

 a granite mountain was in their relative magnitudes. After mentioning 

 that granite veins and granite concretions appeared to be only varieties 

 of each other, it was affirmed to be supported by these circumstances, 

 viz. that, between the great bulk of a granite concretion in strata and & 

 mountain mass or true vein of granite, there has been found to occur, 

 etther a series of minute detached concretions running more or less on- 

 wards to the mountain mass, or a series of concretions, some of which 

 were joined to each other by small processes, or a granite concretion, of- 

 ten of an immense si7.e, was found to be conjoined with the chief body of 

 tlie rock, through means of a granite layer, perhaps not exceeding a few 

 lines in length, and the position of which holds no certain relation to 

 that of the strata. The author next proceeded to examine the relations 

 of granite veins to granite veins, and of granite concretions to granite 

 concretions. The general opinion that of two veins, the crossing vein 

 ftrast be the last formed, was noticed. When comparing tbia ptftVft- 



