622 PROCEEDINGS OF THE BALTIMORE MEETING 



In the same report and on same page, referring to the near approach of the 

 two fields in southern Kentucky, and the slight thickness of presumably worn 

 away strata (150 feet) that would have to be restored in order to unite the 

 two fields, he says : 



"It is impossible to resist the conviction that a million of years ago, or thereabouts, 

 this section still contained a continuous sheet of coal reaching from Wayne and Clinton 

 counties, on the east, across to Edmonson and Hart, on the west. 



"I believe that the uppermost level of caves which remain open in this region were 

 formed during the time when the hills of this section were so continuously capped with 

 the remains of the coal fields that there could have been no doubt as to the continuity 

 of the two fields — the eastern, or Appalachian, and the western, or Illinois, field. This 

 original continuity being granted, the most material question as to the relations of the 

 two coal fields is substantially disposed of. Going north or south of this line, more and 

 more time for the erosion becomes necessary, for that erosion increases progressively, 

 until at Nashville or Cincinnati we require a duration which is probably somewhere be- 

 tween four and eight million of years for the completion of the down cutting from the 

 true coal measures." 



Under "Scientific problems," page 43 of the same report, occurs this state- 

 ment : 



/ 



"Perhaps the most valuable result of the year's work, in a scientific way, is found in 

 the facts that have been gathered, going to show the former existence of a complete 

 union between the eastern and western coal fields across the region occupied by the upper 

 waters of the Green and Cumberland rivers. A treatise on this subject will be found in 

 the Memoirs of the Survey." [This treatise seems never to have been published.] 



"I will here only note that the gap between these fields, now only about sixty miles 

 in breadth, is occupied by the waste of the old Coal Measure rocks that cap nearly etery 

 high hill. The pebbles of the conglomerate, which are peculiar in their nature and 

 easily recognized, are found on every high point in this district ; and in many places the 

 fossil plants of the coal-bearing rocks have been found, showing quite incontestably the 

 former existence of the beds whence they were derived over this area. Less distinct 

 but very suggestive evidence has been found, leading us to raise the question whether 

 the Coal Measures did not cross over the district near Lexington, bringing measures of 

 that age into contact with rocks of a much earlier age." 



In his article, "The origin and nature of soils," 2 occur the following interest- 

 ing suggestions concerning soil inheritance : 



"As soil descends with the wearing away of its materials, it of course is subjected to 

 a constant change in its mineral character. Thus while soil of the district now occu- 

 pied by the rich limestone territory of central Kentucky lay upon the Millstone grit it 

 was doubtless of a sandy and rather sterile nature ; when in its descent it came into the 

 limestone bed it must have been fertile ; still further down, encountering the Devonian 

 or Ohio shale, which because of its mineral character is rather unfit for plants, the soil 

 would again have been reduced to a sterile state. Finally, in downward migration the 

 surface entered the rich fossiliferous beds of Silurian age, and from the storehouses of 

 the ancient marine life it acquired the exceedingly nutritious character of the so-called 

 blue grass soil. 



"As soil migrates downward, the greater part of the debris which it inherits from the 

 rock through which it passes is dissolved and goes away to the sea. There are, how- 

 ever, certain materials which may remain for a long time in the soil because they are 

 peculiarly insoluble. Thus in the limestone soils of Kentucky, the greater part of 

 which are derived from the rocks on which they now lie, we often find many flinty and 

 cherty bits which came into the layer when it was in a geological position a thousand 

 feet or more above the site now occupied by the soil." 



The elaboration of this idea in Shaler's "History of Kentucky," in which he 



8 Twelfth Annual Report of the TJ. S. Geological Survey, pp. 302-303. 



