J. E> Hyde — Notes on the Absence of a Soil Bed. 559 



The Pennsylvanian rocks consist usually of coarse sandstone, 

 frequently feldspathic and sometimes pebbly. One or two 

 coal horizons are present near the base, but the coal is usually 

 thin. Shale beds are not infrequent, but they are usually 

 found higher up in the series, those beds near the contact 

 being commonly sandstones, the so-called " Sharon conglom- 

 erate." Usually the poor outcrops and the short time at hand 

 have prevented the determination of the effect of the Logan 

 hills on the strata of the basal Coal-measures, but at one point 

 in Vinton county and again in Perry county it can be shown 

 that the hills were gradually covered by the Coal-measures 

 and that the first coal swamps were broken by " islands " of 

 Logan, which were later wholly covered by the coarse accumu- 

 lations. Apparently none or, at most, very little of the material 

 was obtained by the erosion of the Logan ; it is much coarser 

 and has come from some other source. 



There is no evidence of marine influence in these basal beds. 

 It was not until later, until the Logan eminences had apparently 

 been entirely covered, that the first marine beds, of which there 

 are several, were formed. 



With the exception of the occasional marine beds which are 

 intercalated, the Pennsylvanian formations of the Appalachian 

 province, including eastern Ohio, are now quite generally held 

 to be the result of some phase of continental deposition. Fol- 

 lowing the post-JVIaxville period of erosion, which developed 

 the sub-Pennsylvanian topography, the simplest interpretation 

 is to suppose slight subsidence sufficient to cause the cessation 

 of erosion and the initiation of deposition, or a climatic change 

 leading to the same result. The area which had been land in 

 post-Maxville time would so continue, except that the topog- 

 raphy would gradually be buried beneath the plain of accumu- 

 eaticg material, over which coal swamps were spread, even 

 while the tops of some of these hills were yet visible. 



In connection with the discussion mentioned earlier, it is 

 to be noted that there are few erosion contacts where one 

 would look for an old soil bed with better reason than at this 

 one. The old land surface, gradually buried under supposedly 

 continental deposits in a climate of at least moderate humidity, 

 it would seem, ought to carry some trace of surface weather- 

 ing if not a well-developed soil bed. The actual contact is 

 seldom seen because of poor outcrops. However, it has been 

 seen at several points and there is no suggestion of pre- 

 Pennsylvanian weathering in the rocks below the erosion plane. 

 In three places the Coal-measures sandstones and conglomer- 

 ates are fused on to the Logan. The writer has in his posses- 

 sion one small hand specimen, one side of which is Logan and 

 the other side the coarse Pennsylvanian sandstone with the 



