PHYSICAL HISTORY OF NEW HAMPSHIRE. 533 



We find peculiarities in the arrangement of land and water in this age 

 not before exhibited. All the porphyritic and Atlantic rocks have be- 

 come solid terra firma, possibly covered by a scanty cryptogamous vege- 

 tation, sufficiently green to redeem the state from sterility. This land is 

 mostly along a central line in the state, passing transversely through 

 New Hampshire to Massachusetts, with an ocean upon each side. 

 That upon the south-east has left no visible traces of its existence in 

 our state, but deposited much sediment over Casco bay in Maine. The 

 land probably extended beyond the Isles of Shoals, so that the deposits 

 of this age are now concealed by water. On the west and north-west 

 side the ocean extended up the Connecticut valley to Groveton, and 

 thence, by way of the upper Ammonoosuc branch, to Umbagog lake, 

 possibly connecting around the north side of the Stratford-Odell Lab- 

 rador granites with a broad expanse northerly, much wider than below 

 and practically without limit, towards the Gulf of St. Lawrence. It is 

 uncertain whether the Connecticut valley ocean connected with the 

 greater body of water washing the east flank of the Green Mountains. 

 The Montalban ridge, between Waterford and Reading, Vt, may have 

 been of sufficient elevation to separate them. If so, the next point of 

 connection on the south was in Connecticut. 



The deposits formed in this period indicate quietness in the waters. 

 They are not now visible south of Bellows Falls in the eastern arm, and 

 are not certainly connected between Berlin and Columbia. They are 

 two or three thousand feet in thickness. 



A marked feature in this ocean appears in its metalliferous character, 

 since pure gold, and the sulphurets of iron, copper, and lead, separated 

 themselves from it. Gold is soluble slightly in ferric solutions; and 

 hence we may infer the presence of per-salts of iron in the water, which 

 leached out from the sandy bottom infinitesimal particles of gold existing 

 as impurities. It was a process of concentration, and agrees with our 

 inspection of the rocks now, for the talcose rocks carry more gold than 

 the gneissic, and subsequently it accumulated still more abundantly. 

 Supposing that ferric sulphates containing gold in solution abound in the 

 Huronian ocean, it is easy to understand how the metal should be pre- 

 cipitated in the pure state. Some deoxidizing agent acts upon the ferric 

 sulphate, and reduces it to the ferrous condition, and at the same time 



