618 E. O. ULKICH REVISION OE THE PALEOZOIC SYSTEMS 



feet; (3) the Antietam sandstone, 700 feet thick, and (4) the Tomstown 

 limestone, with an estimated thickness of 1,000 feet. Sufficient fossil 

 evidence has been procured from these formations to make it reasonably 

 certain that they all belong to the lower Cambrian. The last is suc- 

 ceeded by the Waynesboro formation, which is thought to be middle 

 Cambrian. 



Apparently these lower Cambrian formations lap out northwardly 

 from South Mountain, so that finally only the Harding sandstone, which 

 may be a diminishing extension of the Antietam sandstone, represents the 

 epoch in northern New Jersey. 



The third well developed lower Cambrian sequence in the Appalachian 

 region is found in Chilhowee and other mountains which form the 

 eastern rim of the valley of east Tennessee. Apparently this almost 

 continuous chain of mountains is a large remnant of a great westwardly 

 thrust mass, of which smaller remnants are found to the north in Vir- 

 ginia and to the south in Georgia and Alabama. The base of the Cam- 

 brian is not shown in Chilhowee and Starrs Mountains, but the lowest 

 exposure is probably not far above it. Following the range northeastward 

 to Carter County, the basal formation, here called the Snowbird, is found 

 resting on an Archean granite. 



The Chilhowee sequence, as described by Hayes in the Cleveland folio 

 and Keith in the Knoxville and Loudon folios, begins with a shale of 

 undetermined thickness. This is followed in turn by the Starrs con- 

 glomerate, 660 feet; the Sandsuck shale, about 1,000 feet; the Cochran 

 conglomerate, 1,600 feet; the Mchols shale, 800 feet; the Nebo sand- 

 stone, 500 feet; the Murray shale, 300 feet, and the Hesse sandstone, 

 500 feet, giving a total thickness of approximately 5,500 feet. In the 

 Eoan Mountain quadrangle, as described by Keith in Folio No. 151, the 

 sequence is much the same, excepting that the Sandsuck shale and Starrs 

 conglomerate are not recognized. Instead, the Cochran conglomerate is 

 underlain by the Hiwassee shale, 300 to 1,500 feet thick, and the Snow- 

 bird formation, 700 to 2,000, which, as already stated, rests on the Cran- 

 berry granite of Archean age. In this folio the Shady limestone is 

 represented as following the Hesse sandstone. 



To the west of Chilhowee Mountain — that is, in the valley proper — 

 the Rome sandstone is underlain by two formations supposed to be of 

 lower Cambrian age. These are, namely, the Beaver limestone, 500 feet 

 or more in thickness, and beneath this the Apison shale, of which some- 

 thing like 1,500 feet are seen. Whether these two formations correspond 

 to the formations of the Chilhowee series or represent hiatuses in the 

 Chilhowee section or whether they are really, as is commonly supposed, 



