528 PHYSICAL GEOGRAPHY. 



Essex county, Vt., and elsewhere, as shown upon the third of our map 

 illustrations. The Pemigewasset basin was the largest of any of them. 

 Such a terrible earthquake as must have accompanied the sinking of this 

 land could not very well have passed away without leaving behind a 

 copious outflow of igneous matter. Immediately subsequent to the cat- 

 aclysm, we find indubitable evidence of the largest eruption ever known 

 in New Hampshire. This Pemigewasset area was speedily overspread 

 by a mass of liquid granite, oozing out from the rent in the gneiss, reach- 

 ing down to the igneous reservoir. From the Crawford house to Mt. 

 Lafayette, and from the White Mountain house to Mt. Whiteface, and 

 from Franconia to Conway, the country was flooded. Were there ships 

 of steel they might have floated on this liquid lake, for the surface was 

 as level as the ocean. 



Possibly the outlet of the fiery flood lay along the Saco valley in the 

 line of disturbance. That this flood is not a myth, I would point to its 

 localities, and claim that its surface is well marked to-day. Remove the 

 overlying rock, and the top of the granite will appear as flat as a western 

 prairie. The igneous material I call the granite of Conway, since the most 

 of this town is underlaid by it. It appears also from the Flume to the 

 Basin in Franconia, constituting much of Mts. Profile, Osceola, Fisher, 

 and a host of peaks in the unexplored Pemigewasset area. The Notch 

 has been excavated out of it, also the valleys of the Saco, Swift, and Mad 

 rivers and their tributaries. It is not entire, as when formed, since the 

 tooth of time has gnawed into it, or eaten through in a few instances. 

 Very soon the uneasy earth vomited out another igneous flood, covering 

 the same area, and nearly as great a quantity. Modern volcanoes are 

 apt to throw out lava of slightly different mineral character at succes- 

 sive epochs of eruption. So it was with these ancient New Hampshire 

 vents. The second overflow is a granite, spotted with rounded crystals 

 of feldspar, and scarcely any quartz is present. The first carried a con- 

 siderable quartz. The second verges into a compact feldspathic mass. 

 I call it the Albany graiiite. If you desire to see localities, visit Welch 

 mountain, Mts. Flume and Liberty in Franconia, the summit of Profile, 

 the Twin mountains, and certain peaks in Bartlett and Jackson, besides 

 many elevations in Albany. This material thins out in the east. Be- 

 neath Pequawket it is not over one hundred feet thick, while it is eight 



