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 west sys- 
tem. It is composed of primary and the oldest fossiliferous rocks ; 
having a northerly dip. It occupies ho 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 subietains : but if I mistake 
, it extends + S of the Apr hian chain of 
i Ase tains, ee Pe ee ee = apy ee ey Re ie to which 
Isl dll ¥ shectly call- your’ drsancrnes ‘ 1 system 
only the new red sand as Pa 
may be called the new argent ye Bat I am in doubt 
whether it ought not to be embraced it m. 
sixth system I call the northwest and sovethectut:siyshore 
such is its strike, with a small northeasterly dip. It occurs-in: 
Rhode Island, the southeast part of Massachusetts, and south west 
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. 
regard it as the most recent system in New England ; 
although composed of gneiss and the older slates, it co 
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, etictelpaiigii pn 
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 
SS so that if we find a par- 
trict, (we:may ers SO ‘Upon 
th These 
5 0 
- eiested ie the land. r 
~ 
TR ee a ee 
t Wesswe }' 
