I^RINCIPLES OF STRATiGRAPHIC CORRELATiONS 555 



by faunal and lithological criteria, it is sometimes possible, especially 

 in the more simple cases, to reach a plausible conclusion without such 

 means. We can, for instance, establish readily enough that the seemingly 

 slight break between the Pamelia and Lowville limestones in New York, 

 Kentucky, and central Tennessee is really of high importance. By tracing 

 the formation southward in the Appalachian Valley, we learn that the 

 Lowville expands by additions to its base to over 400 feet of limestone 

 in Hancock County, Tennessee. In other words, that this formation, like 

 the Stones River before it, overlapped northward so that nearly 300 feet 

 more of limestone than reached north central New York was deposited 

 in the southern locality, and all of it following the close of the upper or 

 Pamelia limestone division of the Stones River group. Unfortunately, 

 the proof that the hiatus between this upper Stones River limestone and 

 the base of 400 feet of Lowville represents, as shown in tabular form 

 on page 544, deposition in the Knoxville and Athens troughs of about 

 660 feet of Holston marble, 1,000 feet or more of Athens shale, about 

 500 feet of Tellico sandstone, and 400 to 1,200 feet of Ottosee shale is 

 not so easily procurable. The chief difficulty lies in the fact that the 

 upper Stones River is not found in areas where the Holston attains any- 

 thing like its maximum thickness. Concerning the relations of these 

 two formations the best evidence now at hand was observed in Mulberry 

 Valley north of Sneedville, Tennessee. Here an 80-foot wedge of crystal- 

 line limestone, presumably representing the Holston — which formation 

 seems to have overlapped westward into the Newman trough in north- 

 eastern Tennessee — is intercalated between the top of the Stones River 

 and the base of a 400-foot Lowville section. The contact with both of 

 these formations is unconformable. Regarding the lower hiatus in the 

 Mulberry Valley section, may we not assume that it represents emergence 

 while the remaining earlier beds of the Holston were being deposited in 

 the Knoxville trough? 



Resorting to fossil evidence and to correlation by stratigraphic position 

 and similarity of lithic characters, this assumption becomes reasonably 

 justified. Despite the great time break between the Stones River and 

 the Lowville, their respective faunas are similar in general respects. But 

 this is explained by the fact that both migrated from the Gulf of Mex- 

 ico, so that the Lowville fauna comprises many close derivatives or recur- 

 rences of Stones River species. The Holston fauna, on the other hand, 

 is very different, being of the north Atlantic type. Now, if this fauna 

 had lived in the middle troughs of the valley at the same time that the 

 late Stones River sea occupied basins to the west, it is inconceivable how 

 intermingling of the two faunas could have been prevented when the 



