136 Kindle — Chattanooga Shale in Kentucky. 



tive of the Huron shale. Tour specimen shows even the series 

 of denticles along the front face of the ' premaxillary ' just as in 

 the type specimen." 



The fauna which most geologists have held to indicate a 

 Genesee age for the Chattanooga in Kentucky the writer has 

 found on all sides of the Cincinnati arch in Kentucky, but 

 confined to the lower beds of the formation. There appear to 

 be no good grounds for questioning this assignment of the 

 basal beds of the Chattanooga to Genesee time. The land 

 conditions represented by the unconformity could not then 

 have continued later than the Genesee. Their initiation could 

 not have been earlier than late Hamilton. Limestone of this 

 age underlies the shale near Louisville. Hamilton fossils 

 have been found in the Harpeth River valley a short distance 

 south of the Kentucky-Tennessee boundary. When the Devo- 

 nian limestone has been carefully studied in the intermediate 

 territory in Kentuck} T , Hamilton fossils will doubtless be 

 found in various localities where the rocks of this age have 

 partially escaped erosion. It would appear, therefore, that 

 the unconformity involved a time representing either early 

 Genesee or late Hamilton time, or both. 



The evidence available with regard to the age of the black 

 shale sediments in eastern Tennessee and southwest Virginia, 

 indicate land conditions that were contemporaneous with 

 those which have been described in Kentucky. The uncon- 

 formity at the base of the Chattanooga shale in eastern 

 Tennessee- indicates that a land area existed in that region 

 previous to Chattanooga sedimentation which was doubtless 

 continuous with land conditions in southwest Virginia and 

 central Tennessee and Kentucky, but which may have begun 

 at an earlier period than in Kentucky. The unconformity in 

 eastern Tennessee and southwestern Virginia is followed by 

 shales with a fauna similar to that which we find above it 

 in the Chattanooga in Kentucky. We must conclude, there- 

 fore, that while pre-Chattanooga land conditions may have 

 begun considerably earlier, they did not last appreciably longer 

 in eastern Tennessee and southwest Virginia than in Kentucky. 



* Keith, Arthur, Knoxville, Loudon, Mavnardsville, and Morristown 

 Folios, U. S. Geo!. Survey. 



