  We calculate a sheaf line in CP^3 which is the real line supporting sheaf
points on CP^3 of SL(2,C) Yang-Mills instanton (or SU(2) complex Yang-Mills
instanton) sheaves for some given ADHM data we obtained previously. We found
that this sheaf line is indeed a special jumping line over S^4 spacetime. In
addition, we calculate the singularity structure of the connection A and the
field strength F at the corresponding singular point on S^4 of this sheaf line.
We found that the order of singularity at the singular point on S^4 associated
with the sheaf line in CP^3 is higher than those of other singular points
associated with normal jumping lines. We conjecture that this is a general
feature for sheaf lines among jumping lines.
