9. Brunton Compass
Good to w/in ca. +/- 1 degree.
Metal is bad!

12. Three-Point Method
Remember that strike is the compass direction of a horizontal line on the plane of interest.
Therefore strike can be determined from any two points on that plane at the same elevation (depth).
Dip direction is perpendicular to that. Dip angle can be computed with three points on the plane.

13. Three-Point Method
Can be used for beds that dip gently and consistently over large areas.
Requires determination of elevations and horizontal positions of three points on the surface of interest.
Points must define a triangle with all internal angles > 20 degrees.
Sides of triangle on map should be no shorter than 1.5 cm (otherwise need to survey points in the field).
Construct a the triangle with your points (A, B, C)…