428 CHARLES S. PROSSER 



bands of iron ore, and beds of coal. The Elkgarden (Pittsburg) 

 coal, the noted seam of western Maryland, and known locally as 

 the " Big Vein " or " Fourteen-foot " seam, occurs at the base of 

 this formation. The main mass of coal varies in thickness from 

 ten to nearly fourteen feet, above which are frequently from 

 three to nine feet of alternating coal and black shale which, in 

 the southern part of the George's Creek field, is capped by 

 twenty-five feet of thin black shales in which coal occasionally 

 occurs. 



A seam of coal two and one half feet in thickness is reported 

 m the Consolidation Coal Company's new shaft 92 feet above 

 the base of the Elkgarden coal. From 120 to 140 feet 

 above the top of the Elkgarden is the Tyson (Sewickley) 

 coal varying in thickness from three to seven feet. , Finally, at 

 the top of the formation about 255 feet above the base of the 

 Elkgarden coal is the Koontz (Waynesburg) coal two feet thick 

 and reported to reach a thickness of four and one half feet. The 

 top of this coal determines the upper limit of the Monongahela 

 formation which has a thickness of a little more than 250 feet. 

 Fossils are rare. 



The Monongahela formation was named from the exposures 

 along the Monongahela River in southwestern Pennsylvania, 

 is popularly known as the Upper Productive-measures, is No. 

 XV of the Pennsylvania reports and the Elkgarden formation of 

 the Piedmont folio. 



PERMIAN STRATA (?) 



Dunkard formatio?i. — The largest area of this formation 

 partly underlies the city of Frostburg and covers a considerable 

 tract to the east and southeast of the city. It covers the high 

 part of several hills to the south of Frostburg, extending as far 

 south as Detmold Hill on the western side of George's Creek and 

 the hill south of Pekin on the eastern side. The rocks consist 

 largely of argillaceous shales, which when weathered are reddish- 

 green, with some beds of sandstone, limestone, and coal. A 

 stratum of coal and black shale four feet thick occurs 120 feet 

 above the base of the formation and a drab limestone, five feet 



