128 [Senate 



The volume contains an Introduction of nearly one hundred pages, in which 4;he 

 author has given a resume of the later discoveries in the strata preceding those 

 under immediate consideration, and a description of the principal geological forma- 

 tions known in the State of New-York, their origin and geographical distribution. 

 From his observations upon the Appalachian chain, the author has deduced a new 

 theory of the cause of mountain elevation and the folding of strata, the associated 

 and consequent metaniorphisra resulting from the great accumulation of sediments, 

 and the different results produced by gradual or rapid deposition, etc. 



In some Notes following the body of the Introduction, some arguments are 

 discussed which heretofore have been brought forward by Herschel, Babbage, 

 Ltell, and others, which, so far as they go, sustain the views of the author. The 

 question of the supposed paucity or absence of calcareous matter in metamorphic 

 strata is taken up in one of these notes; and although this is shown to be in ge- 

 neral a necessity from the conditions under which the sediments were originally 

 accumulated, the absence of calcareous matter is by no means universal in meta- 

 morphic rocks. 



This Introduction is in fact a reproduction of Mr. Hall's Address before the 

 American Association for the Advancement of Science, in Montreal, in 1857; or, 

 indeed, we may say that the Introduction preceded the Address, since a consider- 

 able part of it was printed before that time. 



NOTICE. 



When the Appendix F (Contributions to Palaeontology) was originally reported, 

 it was intended to embrace only the new forms of Geaptolide^; the observations 

 on Ehynchonella; the new Genera Skexidium, Amboccelia, and the observa- 

 tions on Athyris, Merista, etc., with descriptions of some new species of Bra- 

 CHCOPODA, subjects which had been determined some time previously. The delay 

 in publishing the Report has enabled the author to add other matter since its date. 

 To the titlepage, therefore, should be added " with additions during 1800." 



