266 Address before the Association of American Geologists. 
river on both sides, at least through a considerable partiof its 
course ; and there is evidence, also, that a» extensive fault in the 
primary rocks runs through that valley. Prof. Mather describes 
“a line of fracture and anticlinal axis” as passing a little west of 
the Hudson river, as well as numerous joints and fractures in the 
valley of the Hudson, which not improbably may bea valley of 
dislocation. Indeed, I doubt not that in most of those cases 
where rivers have found their way through gorges of lofty and 
precipitous ridges, it will be discovered that a break previously 
existed in the strata. To give an example :—the great western 
railroad, leading from Boston to Buffalo, and destined, ere long, to 
reach St. Louis, and ultimately perhaps the Pacific Ocean, is car- 
ried across the. Hoosae range of mountains through a deep cut 
made across the ridges by Westfield river ; and in no other place, 
probably, could it have been. carried urcaghe: But I have re- 
cently satisfied myself that the course of that river was deter- 
mined for a considerable distance, at least, by the existence of a 
wide fissure in the primary strata, which was subsequently filled 
in part by an enormous vein of granite. Is not this a beautiful 
example of prospective benevolence on the part of the Deity; 
thus, by means of a violent fracture of primary mountains, to.pro- 
vide for easy intercommunication. ) through alpine inal 
less ages afterwards! 
‘These slight sketches are sufficient to show that the great and 
striking features of our country are dependant upon a few extend 
ed axes of elevation and depression; and that probably. subordi- 
nate anticlinal and synclinal lines will be found connected with 
most of the minor features of our surface. To trace them all 
out will bea great, yet most interesting work; as it will beto 
ascertain the systems of strata connected with them. Of the , 
latter, we have in New England no less than five or six distinctly 
marked. They are all of them of ancient date, and most of them 
very ancient. The oldest, which may be called the oldest mer 
dional system, because it runs not far from north. and- south, 8 
composed chiefly of gneiss and mica slate; and crosses Masst- 
chusetts near its. centre, including, although this is not certall, 
ova the most elevated ena in New Heslend The second, 
1e em, because it runs 
