Description: Annotated isopach maps supplement the information about thickness with information on the vertical relations of the mapped stratigraphical unit.
The following symbols are added to the contour value:
1) N for contours where the boundaries of the mapped unit are conformable at top and bottom.
2) S for contours of the un-reconstructed thickness of the unit at outcrop.
3) Abbreviated name of overlying unit/abbreviated name of mapped unit for contours where it is truncated by the overlying unit.
4) Abbreviated name of mapped unit/abbreviated name of underlying unit indicating onlap.
The following lines are distinguished:
1) Dotted line shows where surface outcrop of the mapped unit dips beneath cover.
2) Dashed line shows where mapped unit onlaps/overlaps an underlying unit.
3) Crinkled line shows the line of truncation of the top of the mapped unit.