  We apply the method of Diffusion Entropy (DE) to the study of stromatolites
by means of a two-dimensional procedure that makes it possible for us to
compare the DE analysis to the results of a compression method. As done with
the compression method, we analyze two pairs of samples, one biotic and the
other a-biotic. Each pair consists of a target, the putative stromatolite
sample, and of its surrounding matrix. We use two different procedures,
referring to single colors and to a color combination, respectively. We apply
the DE method to both procedures and we find the same result, this being that
the scaling index of the time series stemming from the biotic target yields a
scaling index larger than the scaling indices of the other three curves. We
argue that the DE analysis confirms the results of the compression method.
