AMERICAN GEOLOGY DECADE OF 1850-1851). 445 



In the reports of Lieber matters of both theoretic and economic 

 nature received attention, though an undue amount of space was per- 

 haps devoted to a discussion of the itacolumite, which he considered 

 to be a true sandstone. He differed in this respect with Mr. Tuomey. 

 Its flexibility he regarded as not due to decomposition, but rather to 

 its fineness of grain and admixture of mica or talc, delicately laminated 

 structure, and a certain degree of compactness in the constituents of 

 each lamina. In this he was mistaken. He discussed the origin of the 

 rock, and compared it with the itacolumite of Brazil in its relation to 

 the diamond. 



A peculiar tendency on the part of Lieber to use outlandish terms, 

 particularly Brazilian Portuguese, is manifested in this report. Thus, 

 in his paper on the itacolumite and its associated rocks, he mentions 

 finding the "tapanhoancanga, or canga, which sometimes passed into a 

 reddish quader-sandstone." He also wrote of the u oryctogno$tie" 

 composition of the rock, and designated a prospector as a u costeaner." 

 He classified the igneous rocks of the State, commencing with the 

 newest, as: 



I Eurite and quartz porphyry (?). 

 Trachytic rocks: I Coarse trachyte of eastern Lancaster. 



I Domite, phonolith. 

 Trappean rocks: Diorite and Diorite slate, soapstone (?), Talcose trap (?). 

 Melaphyre, Egeran (?). 

 Aphanitic porphyry. 



Coarse-grained granite, etc., of Taxahaw (syenite). 

 Other granite and gneiss. 

 (The marks of interrogation with some of these denote that their exact relative 

 position is not estahlished. ) 



Lieber's views regarding mineral veins and ore deposits were largely 

 influenced by those of European authorities, but, nevertheless, he 

 entertained certain independent ideas which at this date are instruct- 

 ive. He believed with Werner that the veins were tilled crevices, but 

 thought them to have been tilled from below rather than from above; 

 that is, the minerals constituting the veins he regarded as having 

 been derived from the interior of the planet and brought to the sur- 

 face by mineral waters or steam, where they Avere deposited chiefly 

 in the crevices themselves, the surplus only distributing itself among 

 the surface waters, whence it was afterward precipitated. 



He argued against the idea that the veins had been tilled by the 

 leaching action of water permeating the rocks on either side, saying: 



Entirely the reverse is, however, the case. Thus, minerals which belong to the 

 veins but which are found in the country were in reality derived from the former; 

 the vein crevices were the first reservoirs, and the few scattering particles of the min- 

 erals of tlie veins which we find in the adjacent country rocks found their way into 

 the latter by elimination or secretion and by sublimation from the surcharged vein 

 crevices. 



Granites: 



