Lesley.] 270 [June 20. 



THE OUTCROP BELT OF THE EAST KENTUCKY COAL 



FIELD. 



{To accompany a Map presented to the American Philosophical Society, 

 Jime2Qth, 1873.) 



By Joseph Lesley, 



Late Assistant on the Kentucky Geological Survey. 



Under appointment of David Dale Owen, State Geologist of Kentucky, 

 I began, on the 25th of August, 1858, a Geological aud Topographical 

 Survey of the margin of the Eastern Coal Field of the State, to determine 

 its area, and the number, thickness and attitude of its beds of coal and 

 iron ore ; and to get a reliable base for a future survey of the whole East- 

 ern Coal Field, as far as to the Virginia line. 



The base line of my survey was run upon the common roads of the 

 country ; flying side lines, and in some cases closed looped lines, being 

 carried out sideways to the western outcrops wherever necessary. 



An admirably constructed odometer was used for measuring distances, 

 and a compass with side-telescope and eccentric target for running 

 courses. Aneroid observations, regularly taken at every station, were 

 checked by clinometric measurements made with a vertical circle at- 

 tached to the telescope ; and also by synchronous observations with a 

 barometer stationary in camp. 



The main base line was also carefully leveled for a distance of about 

 two hundred miles with a spirit-level, which was also used on some of 

 the side lines, in order to tie the parts of the work together, and to give 

 the exact datum above tide-water for all principal stations, in view of 

 adopting them as starting points of the contemplated survey of the whole 

 coal field. 



The work thus described was continued from September 1, 1858, to 

 November 1, 1859, seven months being passed in field work, and with 

 the following results : 



1st. A large contour-line map was made on a scale of three miles to 

 the inch, which has never been published. The original plottings were 

 on a scale of five hundred feet to the inch. This map includes only the 

 ground covered by the survey, and shows the positions of towns, couuty- 

 line crossings, coal openings and other points of interest, as well as the 

 crossing of the long east and west base line run by S. S. Lyon, Assistant 

 on the State Geological Survey. 



2d. The map now published for the first time, to accompany this de- 

 scription, was compiled from the survey sheets of the first-named map, 

 from old maps in the Internal Improvement Office, from railway surveys, 

 and from the old State map. 



3d. A base line for future use, extending in a general southwest direc- 

 tion along the strike of the formations, beginning at a point five hundred 

 and ninety-seven feet above tide, close by the town of Grayson, in Carter 



