At the Groton Public Library we found the above book in the James Streeter History Room. Unfortunately, the identity of the carver of the unusual gravestones we discovered in the Avery-Morgan Burial Ground is lost to history, but he is referred to as the Norwich Ovoid Carver.
Particularly in the old Norwichtown burying ground, but also in Windham, Groton, Preston, and Coventry, one finds a small number of large rude semicircular stones that are among the earliest carved stones in the area. They are not just the crude initialed carving found in many inland cemeteries. These stones have obviously been shaped and the fronts smoothed. There is no attempt at designs, but the lettering is deeply and boldly cut and has remained legible for over two hundred years, often without appreciable deterioration. The Groton stones are particularly clear, but may well have been recut. There is something appealing in the elemental cleanness and strength of these early stones. They give one the impression of a society determined to remember its founders forever with no nonsense about it.
~ James A. Slater
(The Colonial Burying Grounds of Eastern Connecticut & The Men Who Made Them)
Besides the four gravestones in Groton, there are thirteen more found in Norwich, three in Preston, two in Windham and one in Coventry.