  We introduce null contractions of the Poincare and relativistic conformal
algebras. The longitudinal null contraction involves writing the algebra in
lightcone coordinates and contracting one of the null directions. For the
Poincare algebra, this yields two non-overlapping co-dimension one Carroll
algebras. The transverse contraction is a limit on the spatial dimensions and
yields two non-overlapping co-dimension one Galilean algebras. We find, similar
to Susskind's original observation of the non-relativistic case, that the
Poincare algebra, written in the lightcone coordinates, naturally contains
Carrollian sub-algebras in one lower dimension. The effect of the longitudinal
contraction, which essentially focusses on the null direction, is to
disentangle the two Carroll algebras that now correspond to the symmetries of
the two null boundaries. The transverse contraction similarly separates the
overlapping Galilean sub-algebras of the original Poincare algebra. We discuss
aspects of the conformal case, where we get lower dimensional Carroll Conformal
algebras and Schrodinger algebras.
