Address before the Association of American Geologists. 269 
Massachusetts, at least all the strata between the Hudson and Con- 
hecticut rivers, and probably a little west of the Hudson, about 
fifty miles in breadth, were affected by this disturbance. The first 
ridge, in going viitenly from the Connecticut to Hudson river, is 
Hoosac mountain, and its eastern slope is gentle, while its western 
side is very steep, and the strata are nearly perpendicular, or ra- 
diate from the axis of the mountain. This appears to have been 
the principal axis of elevation. Next succeeds a deep valley and 
“hen the Taconic range of mountains, which also slopes gently on 
its east side, while its west side is very steep, and its crest very 
narrow. ‘The dip ef the strata is also small on the east side, and 
high on the other. Between this ridge and the Hudson, are no 
tanges of mountains very well marked, but the same large in- 
verted dip continues, and probably more than one folded axis may 
be found in this space. Whether the belt of strata that have 
been subjected to this singular disturbance, is as broad, north or 
south of Massachusetts, I have no certain ranma oh but pre- 
sume it to be as wide and probably wider. 
Tam aware that some able geologists,* whisde opinions % highly 
respect, and who have carefully observed these phenomena, en= 
deavor to explain them by supposing that we have mistaken the 
secondary divisional planes of the rocks for true planes of strati= 
fication ; or that the character of the slaty and calcareous rocks 
of Sieonis and Hoosac mountains has been misunderstood; and 
that they are in fact more recent than the fossiliferous rocks near 
the Hudson ; in other words, that they are metamorphic. But 
for reasons that cannot now be given, for want of time, I have 
been forced to relinquish all these modes of explanation; and al- 
though I will not say that I fully adopt, yet I cannot but look 
With a favorable bias upon the only remaining solution of the 
problem already hinted at, that the strata have ay been toss- 
ed over from their original position. 
‘Let us suppose the strata between Hudson and Connecticut 
tivers, while yet in a plastic state, (and the supposition may be 
extended to any other section across this belt of country from 
Canada to Alabama,) and while only slightly elevated, were acted 
Upon by a force at the two rivers, exerted in opposite directions. 
If powerful enough, it might cause them to fold up into several 
: See Prof. Emmons and Mather’ s views i in the reports of the New York sur- 
vey for 1837, p. 232, and for 1841 . 92 
