Figure 12. Stratigraphic section penetrated by the Amoco No. 1 Wilhour Gas Unit well (shown in figure 13) from the Shade Mountain area of central Pennsylvania. From Pohn and Coleman (1991). Geologic series abbreviated as follows: L, Lower; M, Middle; U, Upper. Stratigraphic thicknesses are estimates. Total depth of the well was 14,737 ft. Gp., Group.