436 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



turbed, and is even thrown up nearly vertically, but the strata 

 generally dip at gentle angles towards the centre of the respective 

 basins. The dip, by observation, at Zanesville, Ohio, is E.S.E., at 

 the rate of thirty-five to forty feet per mile. 



With the exception of slight shades of specific difference, there is 

 a striking analogy between the fossil flora of our western coal-fields 

 and that of the equivalent strata in Europe. The organic remains 

 are chiefly of vegetable origin ; and in the sandstones, shales and 

 slaty clays, almost exclusively so. They consist of Calamites, very 

 abundant ; numerous species of Sphenopterisj Pecopteris, Neuro- 

 pteris and Sigillaria. Specimens of Lepidodendron and Stigmaria 

 are abundant, and beautifully preserved. Some species of Bothro' 

 dendron also occur. Palms are not uncommon, and some remains 

 of ConifercB (?) have been found. I have also obtained remarkable 

 specimens of the stumps of fossil trees (probably palms), found 

 standing erect v>'ith the roots attached, imbedded in slaty clay about 

 twelve miles east of New Harmony ; and slender leaves have been 

 found in great abundance in the near vicinity of the stumps im- 

 bedded in the clay. On the whole, it appears that the resemblance, 

 both in lithological character and organic remains, between our 

 western coal-fields and those of Europe, is close and striking. If 

 not precisely contemporaneous, they may still be considered equi- 

 valent. 



Important beds of argillaceous iron ore have been discovered both 

 in the Ohio and Illinois coal-fields, but few furnaces are yet in ope- 

 ration. The ore of these coal-fields must however ultimately prove 

 an important source of income to our States. 300 feet above the 

 conglomerate a valuable bed of burr-stone exists, from two to six 

 feet thick. It is reported as being equal, at some of the quarries 

 where it is wrought, to the French burr-stone. 



The most productive brines discovered in the Western States have 

 been procured by boring through the lower members of our coal- 

 measures. This is the position of the salt-wells on the Muskingum 

 in Ohio, on the Kenawha and Guyandot in Virginia, on Sandy river 

 and the headwaters of the Licking and Kentucky rivers in Ken- 

 tucky, on the waters of the Patoka and Coal Creek in Indiana, and 

 on Saline and Vermilion rivers in Illinois. 



Immediately beneath the coal-formations of Indiana, Illinois, Ken- 

 tucky and Tennessee, are limestones, mostly of a light grey colour 

 and of a compact texture, including occasionally layers and nodules 

 of chert. Some of these limestones assume the appearance of litho- 

 graphic limestones. The upper beds very frequently have a beau- 

 tiful oolitic structure*. The thickness of this calcareous group 

 varies at^ different localities, being thickest towards the south and 

 thinning out towards the north. On the northern margin of the 

 Illinois coal-field it is so thin and so hidden from view by superficial 

 deposits that it is difficult to detect it ; but on the southern, south- 



* Dr. Troost noticed on the Maramec river in Missouri, the oolitic particles of 

 equivalent beds entirely changed into silex, forming a siliceous oolite. 



