OLD BURYING GROUND, KINGSTON, MA: SYMBOLS & AN ENT

There are a number of  old gravestones at the Old Burying Ground with
 interesting designs & motifs. Some I recognize, others were new to me.

Urn & palm tree at the top of the stone.

Larger urn & palm tree

This next one is a bit more elaborate. The figure in the left hand oval has a circle
of life in her right hand, an hour glass in her left. In the right hand oval the figure
has the hourglass in her right hand a book (a Bible?) in her left.

Angel

A tower?

A broken chained circle.

Besides the symbols there was something I noticed about some of the
headstones at the Old Burying Ground:some of them were turning a
pale red or pink color. Some were just streaked, and others completley
stained. There were about a dozen altogether. Here are two examples:

I had never seen this before and had no idea what was causing it. So I
posted some of the pictures to the Association of Graveyard Rabbits
Facebook page and asked if anyone there might know. Lorinne Massey
suggested it could be tannin from the pine trees on the grounds combined
with rainfall to coat the gravestones. Considering all the stained stones
are located near or directly under the pine trees, it seems to me a logical
explanation.

Finally, one last shot: an ent like tree seems to be pondering the  meaning
of it all, or perhaps is calling for silence: