10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 



relationships at Big Creek and Lost Creek, where the faunizone 

 boundary approximately coincides with the limestone-shale contact, 

 and on Shields Ridge (Piedmont Road, Russell Gap), where the 

 boundary lies within the limestone unit. These observations indicate 

 that, in accordance with its erratically varying thickness, the lower 

 limestone member of the Nolichucky does not occupy the same time 

 span in different sections. Limestone units in the Nolichucky shale 

 are developed erratically at different levels, the only persistent one 

 being the characteristic "ribbon rock" at the top. 



HAMBLEN COUNTY 



Three Springs. — A section of the upper Nolichucky formation is 

 well exposed in a recent road cut on the E. shore of the Three Springs 

 embayment of Cherokee Reservoir (Russellville quadrangle). This 

 locality is in the same outcrop belt as the Big Creek section and is 14 

 miles distant along the strike. Unfortunately, some of the upper ( May- 

 nardville) limestone and its contact with the Copper Ridge dolomite 

 are obscured by incomplete exposures and structural complications. 

 The section was measured in descending order (northward), starting 

 near an old stone bridge, where good exposures in the road cut on the 

 E. side of the road begin. An undetermined portion of the upper lime- 

 stone unit is therefore missing. 



Thickness 

 Feet Inches 

 22. Limestone, in thin beds ribboned with shale or dolomite, 



somewhat more shaly in lower portion Not measured 



Collection cnv/lS, 0-5 feet above base ; 

 Aphelaspis tarda c 



Dytremacephalus angulatus r 



31. Shale 3 6 



30. Shale and limestone, the latter in nodular beds 4 



Collection cnu/15: 

 Aphelaspis tarda c 



29. Shale, partly slumped and poorly exposed. A prominent 

 lens of knobbly limestone 4 feet below top is exposed 



along road 10-30 



28. Shale, with nodular limestone beds 14 



Collection cnt/15 at top : 

 Aphelaspis arsoides c 



Aphelaspis tumifrons c 



Pseudagnostus communis r 



Collection cnt'/15 at base : 

 Aphelaspis arsoides r 



Aphelaspis tumifrons cc 



27. Shale 1 



26. Limestone : massive, granular, with tan-weathering 



stringers 2 



