I know of no raindrop impressions (although one can look along a creek bed
or river after a rain and see rain pits which if covered by sediment would
be preserved.
As to leaves, I would suggest looking at Robert A. Spicer, "The sorting and
Deposition of Allochthonous Plant material in a Modern Environment at
Silwood Lake, Silwood Park, Berkshire, England" U. S. Geological Survey
Professional Paper 1143 (1981) p. 43.
Cores taken from the lake show several layers of leaf litter still preserved
at varous depths. Core RB1 has leaves from the surface to .1 meter. A leaf
layer at .25 m, .575 m, .6 m, 1.0-1.1 m, 1.3 m, 1.45 m.
Core DF1 has leaves in the sediment from .6 -.9 m and from 1.1 m to 1.2 m.
Other cores shown in Figure 44 show other buried and preserved leaf beds in
the shallowest portion of the leaves.
glenn
Adam, Apes, and Anthropology: Finding the Soul of Fossil Man
and
Foundation, Fall and Flood
http://www.isource.net/~grmorton/dmd.htm