before the field season, and should make a fine, even line that
can be wiped off the photograph with a moist piece of cloth or a moistened
soft eraser. These erasures should not damage the photograph if made within
a day, and should damage it only slightly if made at a later time. Ink.flow
pens with standard (moderately thick) points are used for marking rock or
fossil samples. A pencil or ball-point pen used for note-taking must make
easily legible copy that is waterproof and will not smudge. Several extra sets
of pencils and pens should be available in the field camp and an extra set
should be carried in the knapsack.