Maryland Geological Survey 413 



formation. It consist? of alt(M-nating courses of olive-green sliale and 

 thin, fine-grained, flagg)^ sandstone, with an occasional more massive 

 sandstone. The shale is nsiially fissile and hreaks into smooth thin frag- 

 ments witli jiarallel sides, contrasting strongly in this respect with the 

 verv irregular fragments produced by the weathering of the underlying 

 Eomney. Some of the upper beds are more arenaceous and fracture 

 irregularly. Upon weathering the shale becomes greenish or yellowish. 

 A few beds have a decided reddish-brown color. The sandstone is pre- 

 vailingly micaceous and usually becomes fissile upon weathering, breaking 

 into platy fragments. Occasionally a sandstone is more massive and 

 breaks into larger, irregular fragments. The surface of the shale often 

 exhibits " dimpling " and indistinct wave markings. 



The strata of this member usually occupy the lower slopes of the ridges 

 formed by the more resistant sandstone of the Parkhead member. 



The thickness varies from 1600 feet in the eastern sections to 1200 or 

 1300 feet in the sections west of Green Ridge. 



Subdivisions. — The Woodmont member consists of two divisions, the 

 beds containing the Naples fanna and the beds containing the Ithaca 

 fauna. 



Beds Contiiining the Naples Fauna. — The beds containing the Naples 

 fauna form the lower division of the Woodmont member. They consist of 

 olive-green, hard, fissile, argillaceous shale, alternating with numerous 

 courses of thin, fine-grained, flagg}' sandstones. The lower beds are often 

 largely formed of olive-green shale. 



The thickness varies from 500 to 600 feet in the eastern sections, to 

 1200 to 1300 feet west of Green Ridge. 



These beds contain a fauna which resembles, in many respects, that 

 of the Genesee member. The species are chiefly small, delicate-shelled 

 pelecypods and goniatites. Fossils are more abundant in the lower strata, 

 though many beds are nearly barren. 



The following species occur in this division according to the identifica- 

 tions of Dr. J. M. Clarke: Bnchiola reirostriata, Pteroclicenia fvagilis, 

 Tornoceras uniangulare, Bactrites aciculus. 



