342 EARL R. SCHEFFEL 



The region is one of mature topography, with a relief averaging 

 about five hundred feet. 



GEOLOGY 



The geologic maps of the State Survey show exposures in 

 Monongalia County of Carboniferous formations succeeding 

 toward the northwest in approximately parallel belts. The 

 Monongahela River is here practically confined to a course in the 

 Conemaugh, with its valley walls usually showing exposures of 

 most and sometimes all of this formation. 



The members of the Conemaugh are approximately horizontal 

 at Morgantown. Elsewhere the dip is prevailingly toward the 

 northwest with interruptions by mild anticlines and synclines. 

 While a decided dip would undoubtedly have some influence on 

 shdes, it is beheved for the purposes of this paper that the exposed 

 areas of this formation may be considered as horizontal. 



The Conemaugh is composed of alternating beds of shales, 

 sandstones, coals, and limestones, with a total thickness varying 

 from five hundred to six hundred feet. Shale and sandstone mem- 

 bers vary from a few feet to over fifty feet in thickness. About 

 four feet is the usual maximum for coal or limestone members. 



SLIDES 

 ORIGIN AND EXTENT 



Three factors may be considered necessary for the slides dis- 

 cussed. There must be a material which will take the proper 

 consistency, slope, and water. Any of the Conemaugh shales 

 may furnish the material. The degree of slope necessary is practi- 

 cally indeterminable, this varying with water content, thickness, 

 and stratigraphic position of the shale. In extreme cases move- 

 ments of the more fluid type will take place on nearly horizontal 

 surfaces. 



The shales generally are quite fissile, jointed, and slickensided, 

 and tend to become saturated with water, the downward move- 

 ment of which is successively impeded by the less pervious beds. 

 This water evidently has little effect on the stability of the shales 

 where they are not exposed to the air and excessive temperature 

 changes. Cuts exposing unweathered shales show that these will 



