192 



TRANSACTIONS OP THE 



Bails of rich argillaceous iron ore, stratified in beds 

 of shale, alternate with the coal measures here, attaining 

 to the weight of eighty pounds, and they will probably 

 be found co- extensive with some of the coal veins. The 

 value of this description of ore is unknown here, where 

 there exists such an abundant supply of the other varie- 

 ties, attainable at a cheap rate. I observed continuous 

 beds of this ore, some of them of excellent quality, others 

 of a much poorer description^ in situ, at four or live 

 points, both above and below coal. 



A geological examination of these vast deposits of 

 hydrates and haematites, and a collection and exposi- 

 tion of practical facts relative to the numerous manufac- 

 tories of iron in their vicinity, are desiderata. The 

 small district crossed by our section is a part of that ex- 

 tensive system of ferruginous depositories which stretches 

 parallel with the Alleghany through Pennsylvania, Vir- 

 ginia and Tennessee. 



In central Pennsylvania, among the most prolific de- 

 positories of this mineral, the continuous limestone val- 

 leys of Warrior Mark and Nittany must be enumerated. 

 The average level of the former valley is probably more 

 than 200 feet above the transverse or lateral valley of 

 the Little Juniata by which it is intersected, and about 

 1100 feet above tide water. Its surface is very undu- 

 lating, the subsoil chiefly consisting of tenacious clay, 

 intermixed with sand and fragmental sandstone debris, 

 reposing upon a limestone base. Amongst this accumu- 

 lation of detrital remains no traces of secondary rocks are 

 observable; no transported boulders derived from the 

 coal region, whose eastern margin approaches within ten 

 or twelve miles. 



Angular fragments of fine-grained sandstone, beds of 

 sandy grit, and deposits of white chalky marl, which 

 slakes like lime on exposure to the atmosphere, and is 

 used in that state for the purpose of white-washing 



