King's Chapel Cemetery, Boston
The gravestone of Boston shopkeeper, Joseph Tapping, who died in 1678 at the age of 23, is one of the most famous in the city. Just inside the gates fo the King’s Chapel Cemetery is his elaborate carved tombstone.
In the top of the gravestone is the winged skull representing the fleeting nature of life the soul with the admonition “Memento Mori”, “remember death”. Above the winged skill is the hourglass symbolic of time running out.
The top of the Joseph Tapping gravestone
The incised gravestone carving was created by the unnamed carver known simply as “the Charlestown Stonecutter”. In the scene on the face of the tombstone is carved the epic struggle between the death pictured as a skeleton armed with a candle snuffer and an arrow. In this timeless fight, a bearded Father Time is trying to hold Death back and save death for another day.
King's Chapel Cemetery, Boston
Gravely Speaking 
I just saw this headstone today. What does the arrow symbolize?
The arrow represents of the death blow. Much like Cupid who shoots and arrow at a person to make them fall in love, but in this case, Father Time is using an arrow to deliver the final blow.
Correction: The skeleton is using the arrow to deliver the death blow–Father Time is struggling to stop him.
I photographed this stone last year as well as another. I have seen a lot in books and online about this and the similar Foster stone, but have not seen anything on another interesting and similar stone for Mehtabel Sheafe. Did you by any chance see photograph her stone? I am thinking it was in storage for repair for a while (like 75 years) and was reset recently. Here is my blog post about it:
https://symbolism.magnoliasandpeaches.com/?p=3372