Address before the Association of A?nerican Geologists. 269 



Massachusetts, at least all the strata between the Hudson and Con- 

 necticut rivers, and probably a little west of the Hudson, about 

 fifty miles in breadth, were affected by this disturbance. The first 

 ridge, in going westerly 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 

 then 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 of the strata is also small on the east side, and 

 high on the other. Between this ridge and the Hudson, are no 

 ranges 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 [jroad, north or 

 south of Massachusetts, I have no certain knowledge ; but pre- 

 sume it to be as wide and probably wider. 



I am aware that some able geologists,* whose opinions I 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 Taconic 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, 1 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 actually been toss- 

 ed over from their original position. 



Let us suppose the strata between Hudson and Connecticut 

 rivers, 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 in the reports of the New York sur- 

 vey for 1837, p. 232, and for 1841, p. 92. 



