Apparent St ratification of Granite. 



473 



In the conglomerate of the new red sandstone, at the south end of 

 Sugar Loaf mountain in Deerfield, many of the nodules consist of a 

 delicate variety of flesh coloured graphic granite. Whence it origi- 

 nated lam unable to conjecture. 



Pseudo- Stratification of Granite. 



I have met with but one distinct example of this peculiar structure 

 in the State : but it is a case of peculiar interest. It occurs in the 

 patch of granite marked in Worcester. It occupies the hill, 200 or 

 300 feet high, a little northeast of the village. The rock is compos- 

 ed almost entirely of gray quartz and white foliated feldspar, with 

 very little mica, and hardly differs from the sienite of Cape Ann and 

 Q,uincy; although entirely destitute of hornblende. It is quarried 

 in various places on the sides and the top of this hill, and in several 

 of the excavations it exhibits a very distinct stratification. It is also 

 crossed by numerous seams, nearly perpendicular to the horizon, not 

 having any uniform direction : and generally the apparent strata do 

 not correspond on opposite sides of the seams. This seems to result 

 from their elevation or depression on the opposite sides. I satisfied 

 myself, however, that the pseudo-strata conform on all sides nearly to 

 the slope of the hill, being horizontal at the apex, and extending over 

 the sides like the coats of an onion. If this be a fact, it shows conclu- 

 sively that this hill of granite is an enormous concretion. The eon- 

 centric layers, however, do not extend to every part of the hill : and 

 this fact proves that there is no real stratification in the rock. 



Phenomena of Veins and Irregular Protruding Masses of Granite. 



The only modes in which I have met with granite in Massachu- 

 setts are those of veins and protruding masses. In some instances reg- 

 ular masses with parallel planes are seen between the strata of other 

 rocks; and on a superficial view, seem interstratified. But careful 

 examination has always shown me, that such masses either cross the 

 strata in a slight degree, or contract and expand like veins : and 

 seem indeed to be veins coinciding nearly with the strata of the con- 

 tained rock in direction. I can hardly say that I have met with gra- 

 nite as an overleying rock , though a few cases, which will be des- 

 cribed farther on, exhibit this rock in a near approach to such a con- 

 dition. 



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