February 5, 1869.] '-' [Tyson. 



SECTION OF CUMBERLAND COAL BASIN. 

 By Philip T. Tyson op Baltimore. 



It contains the position and tliickness of rocks of the entire ' ' Poto- 

 mac Coal Field," amounting to about 1400 feet. 



In order to have a fixed base I have made the heights on the left hand 

 margin from the level of tide water, beginning at 670 feet. This was 

 obtained from the maps and profiles of the Baltimore and Ohio Railroad, 

 of which I had copies. 



I had also those of the Georges Creek C6al and Iron Company, which 

 connected with the Baltimore and Ohio Railroad. In addition to these I 

 caused numerous other levelings and measurements to be made between 

 Georges Creek and the Savage Mount, and was therefore enabled to con- 

 struct the entire section from actual measurement, with the aid of very 

 extensive diggings, whilst making Geological Surveys for the Georges 

 Creek Coal and Iron Company in 1852. 



This section extends down to the Devonian, and I have also examined 

 and find its beds precisely like those below the Yohogheny Coal Field 

 and the Great Western Field, as seen in the Gap a few miles east of 

 Connellsville. 



The measurements from 670 to 1120 feet were taken on the Savage 

 river and Potomac, From thence to 1349 feet on Mill run, which flows 

 into Georges Creek. From thence to 1443 feet on Laurel run, which also 

 flows into Georges Creek. From 1443 feet on the S. E. face of Dug hill, 

 at the foot of which is Lonoconing. 



