112 JOURNAL OF THE 



Sornetliing may be said l)y way of couclusion concerning the 

 additions to science resulting from the Lieber survey, thongli it 

 will be difficult to discuss these intelligently until the regions 

 and problems he studied can be W'Orked over again in the light 

 of more recent investigations. The region in which he labored, 

 embracing a considerable area of the crystalline rocks of the 

 south Appalachian region, is one of great geologic and economic 

 interest and importance. The general problems that interested 

 Lieber more especially were the characteristics, classification, 

 nature and origin of the metalliferous veins, the character and 

 age of metamnrphic rocks, including the age and history of the 

 Appalachian mountain region and especially of the itacolumite 

 formation, and the character and relative age of the eruptive 

 rocks. It must be borne in mind that the science of petrography 

 was in its infancy, and the use of the microscope in the study of 

 crystalline rocks almost unknown at the time of Lieber's work; 

 and yet it may be fairly claimed that he added considerably to 

 our knowledge and understanding of these problems connected 

 with the crystalline rocks and "vein geognosy" of the southern 

 Appalachian regions. Those interested in the subject should 

 read his four annual Reports where his conclusions are stated at 

 length, as the limits of the present sketch preclude a full state- 

 ment of them here. One of his conclusions — as to the age of 

 the itacolumite series of rocks and the neighboring crystalline 

 schists of portions of upper South Carolina, Western North 

 Carolina and upper Alabama — may be stated here as of special 

 interest; and it will be better to state it in his own words:* 



If, then, we remember that in some localities the itacolumite, or rather the 

 qnartzite stratigraphically identical with it, has already been established to be 

 of lower Silurian age, and also take into consideration that appearances cer- 

 tainly favor the view that the crystalline slates of Alabama belong to that 

 geologic period, we may, it is true, still justly regard the proof as imper- 

 fect, but we cannot deny that the weight of evidence is greater for than against 

 the supposition that the itacolumite rocks of the South are lower silurian, and 

 that such also is the probable age of all the crystalline slates of the Allegha- 

 nies in general. 



*See The Itacolumite and its Associated Rocks— Supplement to The Third Annual 

 Report of the Survey of S. C, (1858) p. 149. 



