; 



318 Sketch of the Geology of 



forms the place of the junction of two great systems of 

 strata. 



In my Report on the Geology of Massachusetts, I 

 have described the northeast and southwest system as 

 crossing the easterly part of that State^ and probably 

 embracing a portion at least, of the Allegany mountains, 

 and perhaps connected with Beaumont's vast Pyreneq- 

 Appenine system. I have also, in the same work, de- 

 scribed a northwest and southeast system ; though in 

 some doubt whether such a system exists on this con- 

 tinent. But if I am not mistaken in my statements about 

 the rocks in Maine, it would seem that such a system 

 must be admitted to exist. 



Gneiss. 



One has to go only a few miles northerly or north- 

 westerly from Portland, to find himself entered upon a 

 vast region of this rock. How far it extends in those 

 directions I am unable to say: but presume, from all that 

 I can learn, that it constitutes a larger part of the surface 

 of Maine than any other rock. In passing along the 

 coast towards Brunswick, w^e strike gneiss about three 

 miles from the city ; and I am informeil that it continues 

 northeasterly as much as sixty or seventy miles. In 

 going west from Portland, we find a remarkable hill of 

 gneisS; not more than a mile or a mile and a half from 

 the city. It is easily mistaken for a ledge of granite, on 

 account of the indistinctness of the stratification. But 

 the schistose arrangement of the ingredients is easily dis- 

 coverable. I am inclined to believe, that a judicious ex- 

 ploration of this spot would prove, that an inexhaustible 



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