Feotherdonhaugh^s Geological Report. 



37 



As the rormations hitherto considered have a character be- 

 longing to them which is not common to the incumbent beds, 

 especially on this continent, a few remarks here on the highly- 

 inclined strata of the stratified masses serving to develop some 

 important principles of the science, cannot but be useful to 

 the practical student. 



In every part of the world where geological investigations 

 have been made, the rocks hithei to enumerated have gene- 

 rally been found, and always in the same determinate order, 

 with the exception of that occasional irregularity before 

 alluded to amongst the ignigenous rocks. They occupy, also, 

 more extensive areas than the rocks which have succeeded 

 to them, from which it may be inferred that the causes which 

 produced them were more intensely in action. Granite is 

 every where. The body of the great Himalaya chain in India 

 is gneiss ; it abounds also in the most northern known lands, 

 in the Andes, the Alps, and the Pyrenees. In western Africa 

 the rocks forming the banks of the Rokelle are granite, gneiss, 

 mica slate, and the lower slates. Upon the northern Atlantic 

 frontier of the United States, the whole series of these last- 

 mentioned rocks can be traced, alternating variously with 

 each other, uninterruptedly to the Avestern lines of Massachu- 

 setts and Connecticut, with the exception of the carboniferous 

 sandstone along the line of the Connecticut river. Further 

 south, the same zone of primordial rocks is to be observed 

 from the falls of the rivers that empty into the Atlantic, to the 

 extensive Atlantic* primary chain, embracing those auriferous 



+ In my report of last year, at page 33, the necessity of giving a general name to 

 this chain was urged, on account of the confusion produced by the varioutj desig- 

 nations it receives in different localities, such as Blue ridge, Alleghany mountain, 

 iron mountain, Unaka, &c.^ and Atlantic Primary Chain was proposed as express- 

 ing its general and predominant character. The mineral structure of this chain 

 has never been thoroughly examined, but, at numerous points Vt^here I have visited 

 it, it varies from the primordial rocks to some of the members of the Silurian sys- 

 tem. At West Point, where it is divided by the Hudson river, the predominant 

 chaxacier is gneiss - at Harper 'ii Ferry, it is a variety of stratified slat^j in Madison 



