NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 7 



The following comments may be made about this section and the 

 contained fossils : 



The Maryville formation here consists mostly of dolomite, except 

 in the uppermost portion which is rather pure, crystalline or oolitic 

 limestone. The contact of the formation with the underlying Rogers- 

 ville shale is very sharp. Presumably the Middle-Upper Cambrian 

 boundary lies somewhere within the Maryville, since the uppermost 

 portion holds a faunule of the Cedarm zone, of very early Dresbachian 

 age. The author was unable to find fossils in the lower parts of the 

 formation in the Rogersville area. However, a collection in the U.S. 

 National Museum (loc. 107x, 11 miles NW. of Knoxville) mentioned 

 by Walcott (1916b, p. 394) yielded the types of Asaphiscus glaher 

 Walcott and a species of Olenoides. These are undoubted Middle 

 Cambrian fossils and were certainly collected from limestone of the 

 Maryville formation, or at least its equivalent in the Conasauga group. 



The Nolichuck}'^ formation at Big Creek and in other sections studied 

 in the Rogersville outcrop belt, as well as at many other localities, 

 consists in ascending order of four members : a shale, a limestone, 

 another shale, and the uppermost limestone. The lower limestone mem- 

 ber, although very thick and conspicuous in the present section, is 

 quite variable in thickness. It is essentially absent from some of the 

 sections north of Clinch Mountain, such as the Thorn Hill and Pur- 

 chase Ridge sections, and even from the section on Price School road 

 which is not far from Rogersville and in the same outcrop belt. At 

 several localities this limestone is in part of algal origin (Oder and 

 Bumgarner, 1961). Geologists who discussed the stratigraphy of 

 northeastern Tennessee generally recognized a Maynardville lime- 

 stone, either as a member of the Nolichucky or as a separate formation. 

 In the typical area, in the Maynardville quadrangle, there is essentially 

 one limestone succession above the shale of the lower Nolichucky, and 

 this was named the Maynardville limestone. It includes at least por- 

 tions of Crepicephalus and Aphelaspis faunizones (see discussion of 

 the Hurricane Hollow section) . The question arises whether in areas 

 where the upper Nolichucky consists of two limestone units separated 

 by a shale, the name Maynardville should apply to this entire complex, 

 or to the upper limestone alone, the characteristic thin-bedded lime- 

 stone ribboned with shale and dolomite. Since the author's purpose 

 is not to discuss stratigraphic nomenclature, the more noncommittal 

 attitude of assigning all the strata in question to the Nolichucky is 

 adopted, without implying any judgment on the validity and bound- 

 aries of the Maynardville limestone. 



The faunules listed in the section show that the basal Nolichucky 

 shale holds essentially the same fossils as the uppermost Maryville 



