128 ANNALS NEW YORK ACADEMY OF SCIENCES 



them. Below the ore, tliere is also more or less shale intervening before the 

 top of the sandstone and couitjlonierate basement is reached." 



G. P. Grirasley (130, p. 74) : 



"The rooks of tlu' Clinton scries in this state arc sliah\s. clays, sandstones 

 and an absence of limestone. If there was orij^inally a l»ed of limestone now 

 replaced by ore, the stratum was a very irivj^ular one, varying in thickness 

 from 6 inches to '.> feet. It expanded and contracted from i)]ace to place in a 

 most irregular mannci-; a relation very unusual fr)r limestone, but often present 

 in sandstones and other shallow water rocks. I5y the theory of original sea 

 deposition of this iron ore, it would be formed in the Clinton sea in the same 

 manner as sandstones and shales. The iron was precipitated and mixed with 

 sand and clay in which fossils were preserved. The oolitic structure would 

 imply a concretionai\v deposit, the iron ore being pi'ecipltated around sand 

 grains in concentric form. In some portions of the sea, as in the Keyser area, 

 there was only a slight precipitation of iron in the sand. 



"The difficult factor to account for in this theory is the quantity of iron 

 available for this deposit in the Clinton sea, apparently not duplicated at any 

 other time before or since. There must have been at this time an exceptional 

 quantity of iron present ; its source is difficult to explain. There are thus 

 encountered in both theories factors almost impossible to account for ; but it 

 seems to the writer that the theory of original deposition offers a more satis- 

 factory explanation of the origin of these West Virginia Clinton ores than 

 that of replacement." 



One of the most complete publications on the Clinton ores has been 

 made by S. W. McCallie (216) for the Georgia Geological Survey. He 

 agrees with Eckel and Smyth in placing the origin as original sedi- 

 mentary deposition, but differs from them as to the source of the iron. 

 He maintains that it came originally from large deposits of glauconite 

 marl. 



Both J. S. Newberry (232) and T. C. Chnmberlin (53) conclude tbat 

 the Clinton ores of their states were formed by original deposition of 

 their iron content, similar to the Swedish lalce ores. 



H. D. Eogers (290, p. 739) : 



"The regular ores of the Surgent (Clinton) series are to be regarded as 

 among the pei'manent constituent strata of the formation, and as having origi- 

 nated with other sedimentary materials in the form of very extended, but 

 thin, sheets of ferruginous matter, covering at successive epochs the wide floor 

 of the quiet Appalachian sea." 



He goes on to say that the source of the oxides has not been deter- 

 mined. He acknowledges that much secondary enrichment has taken 

 place by enormous quantities of ferruginous matter diffused in marls, 

 slates and shales in contact with the ore bodies, being dissolved in tho 

 form, of sulphate and then redcpositing the iron in the ore beds, reaction 



