WEST VIRGINIA GEOLOGICAL SURVEY. 37 



DETAILED STRUCTURE. 

 General Features. 



As shown by Map II, the structure of Lewis and Gilmer 

 has been only slightly disturbed by upward or lateral move- 

 ments of the earth's crust. 



There is a gradual rise from the northwest to the south- 

 east, accentuated by the Chestnut Ridge Anticline and inter- 

 rupted by the Grassland Syncline, structural features, both of 

 which pass entirely across the area. The pitch of the rocks is 

 nowhere excessive, being usually hardly perceptible to the eye, 

 careful levels on the coals being necessary to determine the 

 nature and rate of change. The lowest point of structure 

 found in either county was near Spurgeon, in northeastern 

 Gilmer, where the Pittsburgh Coal descends to less than 425 

 feet above sea level, along the Robinson Syncline. The high- 

 est structural level is at Cleveland, at the common corner of 

 Lewis, Upshur and Webster, where the Pittsburgh Coal hori- 

 zon belongs above the top of the mountains, and would have 

 an elevation of 2375 feet above sea level. The general direc- 

 tion of most of the anticlines and synclines is, roughly, north- 

 east and southwest, corresponding closely to the trend of the 

 Appalachian Mountain System. Only one anticline and one 

 syncline extend entirely across the two counties. There are 

 no features of unusual interest or occurrence. 



The structure map, on the whole, harmonizes closely with 

 those previously issued by the Survey, contiguous to this area, 

 one for Calhoun, Roane and Wirt, one for Ritchie, and one for 

 Doddridge and Harrison. The maps for Calhoun and Ritchie 

 are based on the Washington Coal, 500 to 600 feet above the 

 Pittsburgh, so that being on different strata, the contours of 

 the two maps do not join with that for Gilmer, but when the 

 proper interval is allowed there is little discrepancy. The 

 map for Doddridge and Harrison is based on the Pittsburgh 

 Coal, and the contours join exactly along the most of this line. 



