DR. E. HULL ON THE PHYSICAL GEOLOGY OF TENNK8SEE, ETC. 69 



7. On the Physical Geology of Tennessee and Adjoining Disxeicts 

 in the United States of America. By Edward Hull, M.A., 

 LL.D., r.E.S., r.G.S., late Director of the Geological Survey 

 of Ireland. (Read December 10, 1890.) 



Contents. 



Part I. § 1. Introduction. 



§ 2. Physical Features. 



1. The Valley of East Tennessee. 



2. Cumberland Plateau; Walden's Ridge. 



3. The Sequachee Valley. 



4. Rocks of the Cumberland Table-land. 

 Part II. Development of the chief Physical Features. 



I. The Cumberland Plateau. 



1. The Stratification. 



2. Epoch of Gi-eatest Terrestrial Movements. 



3. Direction of Greatest Vertical Movement and Erosion. 



4. Formation of the Cumberland Plateau. 



II. The Gorge of the Tennessee through the Cumberland Plateau. 



Part I. — § 1. Introduction. 



A recent visit to the Southern States of North America induces me 

 to lay before the Society some observations on the physical aspect 

 of a peculiarly interesting region traversed by the Tennessee River in 

 the State of the same name and the bordering districts. The geological 

 structure of this district has been ably described by Professor James 

 M. Safford, the State Geologist *. The region is now in process of 

 being re-surveyed topographically and geologically under the direc- 

 tion of Major Powell, U.S. Geological Survey, to whom I am much 

 indebted for kind assistance in procuring maps and informa- 

 tion t. In the present communication I do not propose to enter at 

 any length into the geological structure of the district here described, 

 but only to single out the most striking features connected with its 

 physical structure, and to endeavour to show how they can be 

 accounted for upon those principles of interpretation which, after 

 many years of discussion and research, are generally adopted 

 amongst geologists. Amongst others we shall have to explain the 

 formation of table-lands, and of the erosion of the gorge by which a 

 great river, the Tennessee, traverses a mountain-plateau in pursuing 

 its way towards the ocean, instead of taking a much more direct 

 course. 



■* ' Report on the Geology of Tennessee' (1869). 



i' The sheets, prepared in the Geological Survey Office, are on a scale of 



, and are contoured at intervals of 100 feet vertical. A very fine minera- 



1:^5,000' 



logical map of Tennessee, on a large scale, constructed by Major Kelly, is 



placed in the Town Hall of Chattanooga. 



