400 A. F. FOERSTE LIMESTONES OF TENNESSEE AND KENTUCKY 



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Laurel limestone rests on claj^ey material (})late 36, figures 1 and 2). 



Stratigra|)hically this undoubtedl}'^ represents the Osgood cla}^ of Ken- 

 tucky, but lithologically it is much less shaly. 

 It occurs in thicker laj'ers, some of which 

 are slightl}'^ indurated, especially in the upper 

 part of the section. Tlie indurated layers are 

 slightly lighter in color, thus producing a sort 

 of banded appearance. The total thickness 

 of the clayey material is 14 feet. 



A much greater approach to the lithologi- 

 cal characteristics shown by the Osgood clay 

 sections in Nelson county, Kentucky, may be 

 seen about a quarter of a mile north of Bled- 

 soe (figure 1, locality 3), on the northeast side 

 of the railroad trestle, north of Frank Karl's 

 house. At this locality, which is about 14 

 miles east of South Tunnel, the Osgood clay 

 is about 20 feet thick. It is a shaly clay, 

 rather dark where not weathered, and the 

 lower part is tinged with ])urple, resembling 

 quite closely various exposures east of Bards- 

 town, in Nelson county, Kentucky, and in 

 the northern i)art of that county, along the 

 Bullitt county line. 



At South Tunnel the Clinton is first seen 

 in the form of fragments of fossiliferous chert, 

 east of the railroad and a short distance south 

 of the fourth cut. The full section is seen a 

 quarter of a mile farther on, at a fifth cut. 

 The Clinton limestone is about 7 feet thick 

 and tlie upper ]jart contains a considerable 

 quantit}'' of fossiliferous chert. Loose frag- 

 ments of this chert may be traced south- 

 ward through the fields for sev'eral hundred 

 yards from the last exi)osure. The lower part 

 of the Clinton is a bluish limestone, contain- 

 ing much less chert and only a few fossils. 

 It resembles so much the top of the imme- 

 diately underlying Ordovician rock, in which 

 fossils are also scarce, that it requires patience 

 to determine where to draw the line between 



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the Silurian and the Ordovician rocks. 



