Address before the Association of American Geologists. 267 



direction with that of the Alleghany mountains, and probably 

 forms a part of their most easterly ranges. It extends, also, 

 through almost the whole of Maine. It is composed chiefly of 

 primary rocks. The third system, I call the east and icest sys- 

 tem. It is composed of primary and the oldest fossiliferous rocks ; 

 having a northerly dip. It occupies no great space in New Eng- 

 land. But perhaps the east and west ridges of mountains de- 

 scribed by Dr. Houghton, on the south side of Lake Superior, 

 may belong to the same system ; although I think we ought to be 

 very cautious in referring the rocks of widely separated regions 

 to the same system ; especially if their strike is merely parallel, 

 and not upon the same continuous line. The fourth system em- 

 braces the rocks from gneiss upwards, so as to include most of the 

 clay slate and Silurian groups. The strata have a perpendicular 

 or inverted dip. I call it the Hoosac or Green mountain system, 

 because it embraces most of those mountains : but if I mistake 

 not, it extends through the whole of tlie Appalachian chain of 

 mountains, and possesses some remarkable peculiarities, to which 

 I shall shortly call your attention. The fifth system embraces 

 only the new red sandstone and its associated trap; and hence it 

 may be called the new red sandstone system. But I am in doubt 

 whether it ought not to be embraced in the fourth system. The 

 sixth system I call the northwest and southeast system, because 

 such is its strike, with a small northeasterly dip. It occurs in 

 Rhode Island, the southeast part of Massachusetts, and southwest 

 part of Maine : but it is very limited, unless it should be found 

 that the four ranges of mountains, described by Dr. Richardson, 

 in the extreme northwesterly part of this continent, belong to it. 

 I regard it as the most recent system in New England ; because, 

 although composed of gneiss and the older slates, it corresponds, 

 in strike and dip, with the eocene tertiary on Martha's Vineyard ; 

 and probably both were elevated at the same time. 



The whole number of systems of strata, corresponding in their 

 general strike and dip in this country, will undoubtedly be found 

 to be much greater than those now described. Nor should I have 

 mentioned these, which have been observed in a limited district, 

 had I not great confidence in the uniformity and great extent of 

 the geological features of this country ; so that if we find a par- 

 ticular arrangement in one district, we may safely presume upon 

 the existence of its counterpart in other parts of the land. These 



