Rocky Moutitains. 437 



evidently belonging to the oldest depositions of that rock. It 

 is for the most part distinctly stratified, and in all cases its 

 stratifications are inclined. It consists of grains of quartz 

 united by a scanty cement, and usually more or less rounded 

 as if by attrition and the operation of currents of water. 

 These fragments vary in magnitude from the finest sand, to 

 boulders of several pounds weight. Among the Alleghany 

 mountains, are many extensive beds of pudding stone, or 

 coarse conglomerate, usually consisting of white quartzy peb- 

 bles in a cement often highly coloured by oxide of iron. It 

 is also to be observed that this formation of transition sand- 

 stone, sometimes embraces extensive beds, whose integrant 

 panicles have by no means the appearance of having been 

 rounded by attrition. As in the case of almost all the rocks 

 of secondary formation, there appear to have been periods 

 during the time of its deposition when the waters of the 

 superincumbent ocean ceased to throw down the mechanical 

 debris of former rocks and deposited earthy matter from a 

 state of chemical solution. 



The Alleghany mountains in New York, Pennsylvania, 

 Maryland, and Virginia, consist principally of rocks belong- 

 ing to the transition class; and among these, sandstone is 

 perhaps of more frequent occurrence than any other aggre- 

 gate. Mr. Maclure has not considered the sandstones of the 

 Alleghany mountains generally, as belonging to the old red 

 sandstone formation of Werner; and it must be acknowledg- 

 ed there is some difference at least in colour, between the 

 ferruginous sand rock, which appears on the shore of the 

 Tappan bay, near Nyac, and extends south and west through 

 Newark, Amboy, and Brunswick, to Norristown in Penn- 

 sylvania; and that which forms the body of the Cove, Side- 

 ling and Alleghany ridges farther to the west. But we can- 

 not discover so marked a difference between the sandstone 

 of the localities last mentioned, and that which occurs about 

 the south mountain in Pennsylvania, that at Hagarstown in 

 Maryland, and near Harper's Ferry, in Virginia, which he 

 considers as the old red sandstone. Indeed this last appears 

 to us in almost every respect, to resemble the inclined sand- 

 stone which prevails so generally throughout the middle and 

 eastern ridges of the Alleghany mountains in Pennsylvania, 

 and Maryland. We have already stated the opinion in part 

 sanctioned by the observations of Maclure, that the old red 

 sandstone, is the substratum of the part of the secondary 

 formation south of lake Ontario. If this be the case, what 



