Geological Nomenclature. 147 



mistakes, as he will feel no interest in such apologies. I now 

 state, that I have traversed the transition range from Mas- 

 sachusetts line to Hudson river, in fifteen places, since the 

 first part of this survey was published, for the purpose of as- 

 certaining the true superposition of rocks in this most com- 

 plicated and difficult geological theatre. 



The argillite, under which the granular limestone passes 

 near Massachusetts line, is certainly the very same contin- 

 ous rock, which forms the Cohoes falls, and the bed and 

 banks of the Hudson from Baker's falls to Newburgh, near 

 the Highlands. All the intervening rocks lie in a kind of 

 inclined trough in the argillite. We have no primitive argil- 

 lite in our district, if organic remains form the characteristic 

 distinction. Neither do I believe there is such a rock as pri- 

 mitive argillite on this globe. This is Bakewell's opinion ; 

 and though I have often changed mine, I now believe he is 

 correct, and that the bassetting edges of the same rocks pre- 

 sent a more primitive appearance in all cases ; and that this 

 fact has led geologists into ruinous errors. 



First graywacke, sparry limerock, calciferous sandrock, 

 and metalliferous limerock may be seen in regular order of 

 superposition, between Massachusetts line and Hudson river. 

 West of Cohoes Falls the same rocks occur, and at Alexan- 

 der's bridge the second graywacke overlies the whole. 



We now pass over the second and third occurrence of the 

 same rocks on our geological profile, and recommence with 

 the same calciferous sandrock west of Little Falls. Here we 

 find the metalliferous limerock, and second graywacke so 

 perfectly characterized, that mere inspection is conclusive. 

 The graywacke passes directly under the millstone grit in 

 fair view in Starch Factory Creek, Meyer's Creek, and Steel's 

 Creek.* 



Here too we see the millstone grit pass under the salife- 

 rous rock. This may be seen eighty miles in a lateral direc- 

 tion towards lake Ontario. The bassetts of this rock, of the 

 saliferous and of the ferriferous, may all be seen in this or- 

 der of superposition all the way to lake Ontario. 



We may now go to our next starting point, Genessee 

 Falls. Here we see the saliferous rock. Ferriferous lias, 

 and geodiferous, lying upon each other as distinctly as a 



* Places set down on the geological profile will be referred to without any 

 farther description. 



