Shaler.] 114 . [February 1, 



the stream, in the latitude of Charleston, S. C, several parallel 

 ridges were discovered which had a height of over' one thousand 

 feet; these ridges were, in their course, approximately parallel to 

 the coast, and to the trend of the Alleghany range. The symmetri- 

 cal relations of direction and arrangement existing between these 

 submarine ridges and those of the Alleghany chain, at once sug- 

 gest the existence of some relation of a genetic kind. The fact, 

 hitherto unnoticed, of the existence of a ridge occupying a somewhat 

 intermediate position between the Alleghanies and these submerged 

 mountains, makes it not at all improbable that deeper down, beneath 

 the more recent strata, there may be other similar ridges. I have else- 

 where endeavored to show that the formation of mountain chains is 

 necessarily limited to the land areas, or at least to those areas where 

 there is no deposition of sedimentary material taking place. If this 

 principle be correct, then we shall be safe in assuming that the sub- 

 merged mountains, in the path of the Gulf stream above referred to, 

 were formed above the level of the sea, and have since been sub- 

 merged. Assuming that the continent has moved, as a whole, in this 

 change of level, we should be compelled to suppose that the Allegha- 

 nies had lost over ten thousand feet of their altitude by this subsidence. 

 It is possible, however, and this view derives probability from several 

 sources, that the subsidence took place through the downward flexure 

 of the section lying between the base of the Alleghanies, and the point 

 where these submerged chains now lie. We shall see hereafter that 

 there is evidence at hand to show that the coast of the continent, from 

 a point somewhere between New York and the Chesapeake, is grad- 

 ually subsiding, and that this subsidence has already gone so far as to 

 depress recent accumulations to the depth of near one hundred feet 

 at some points. 



The question next in importance is that concerning the time of up- 

 lift of the Richmond axis. Passing to the east from Richmond we find 

 at the distance of a few miles a set of coal bearing beds, dipping 

 steeply to the west. The shafts of the coal field mines enable us to 

 be sure that this dip amounts to over one thousand feet in the dis- 

 tance of three or four miles, at those points where the dip is least, and 

 to two or three times this declivity at other points. The degree of 

 inclination of these beds, together with the evidences of intense dis- 

 turbance visible in every section through the coal bearing part of the 

 series, makes it evident that they could not have been laid down in 

 their present position. The presumption always is that coal beds have 



