Procedure:

1.   Both dome structures and basin structures form circular outcrop patterns (below).  Note in particular the direction in which the strata appears to point with a “V” shape, called an “outcrop V”.  This effect is caused by the shape of the topography where resistant formations are eroded.  Note that in a structural dome the oldest rocks crop out in the center of a dome.  Note that in a structural basin the younger rocks crop out in the center of the basin.

2.   On the maps shown below add strike and dip symbols to show the geometry of the strata.  Strata dips away from the center of the dome, and towards the center of the basin.  Label the oldest map unit in each of the map views with an “A”.  Label the rest of the units sequentially in each map.

3.  Examine the stereo pair of photographs of plunging folds in Wyoming.  Look for outcrop V’s to indicate which way strata is dipping.  Use a pocket stereoscope (if available) to get a three dimensional image and help determine the direction of outcrop V’s.  With practice, one can learn to merge the images without the use of the stereoscope. Add strike and dip symbols to the photos to show which way the beds dip.  Label the anticline and the adjacent syncline with fold axis symbols along the axial traces.  Place an arrow on each axis showing the plunge direction.