North East and South West System. 



533 



observed in the argillaceous slate of Guilford, Vt. has led ine to sus- 

 pect that this also may belong to the same system. But to render it 

 certain, the formation should be examined farther north, in Vermont 

 and New Hampshire. The mica slate associated with this clay slate 

 on the east in the southwestern part of New Hampshire, should be 

 examined with the same object in view : for I have observed this also 

 to bear too much to the northeast and southwest to belong to the me- 

 ridional systems, except as a local anomaly. 



I have particularly described under sienite, a limited formation of 

 hornblende slate, and mica slate in Whately, running in a direction 

 which corresponds nearly w 7 ith the northeast and southwest system. 

 If I do not misrecollect, the same series of rocks, embracing serpen- 

 tine and verd antique marble, west of New Haven, have a similar di- 

 rection. Perhaps both these cases are insulated parts of this sys- 

 tem. 



I think it most probable that the northeast and southwest ranges 

 which I have now described, belong to a very extensive system of el- 

 evation, of w 7 hich the Allegany mountains form a part. Another 

 range of strata of vast extent, doubtless a part of the same system, 

 can be traced from the river Saguenai, 100 miles east of Quebec, to 

 Lake Huron. These consist of gneiss, mica slate, greenstone, sie- 

 nite, &c. and have been regarded by Dr. Bigsby as the most recent 

 of the primary rocks.* But if we take Beaumont for authority, even 

 these extensive ridges constitute but a moiety of this system. It is 

 his Pyreneo-Appenine system : and it includes the whole of the Pyr- 

 enees, a part of the Appenines, the mountains of the Morea, a part 

 of the Hartz Mountains, Mount Atlas, and other ridges in Africa, 

 particularly in Egypt, the Carpathian Mountains, Mount Carmel, and 

 Sinai in Palestine, a part of the Caucasian chain, and of the Ghauts, 

 forming indeed, a set of parallel ridges around the whole globe; and 

 being the most extensive and remarkable system that has yet been 

 traced. 



I ought perhaps, how r ever, to suggest the possibility, that the rocks in 

 Massachusetts, which I have described as belonging to this system, 

 may be found connected with some other. For the strata certainly 

 for the most part, run nearer north and south by a few degrees than 

 the general course of the Alleganies. 



I have not found any of the more recent rocks in Massachusetts 



* Philosophical Magazine Vol. 2. N. Series p. 219. 



