I noticed recently on a Wellesley map that a big boulder at the intersection of Grove Street and Dover Road was labeled Problem Rock. I’ve gone past the rock a zillion times in the past and never realized it was anything special.
Though the name of the rock is appropriate: It actually is a problem trying to get a good look at Problem Rock without getting hit by a car. But I did it on your behalf early one morning without incident.
Here’s the story about this rock (this post has been updated in 2020).
It is cited in The Geological Story of Wellesley, a 1961 book (revised in 1984) available from the Wellesley Conservation Council (now the Wellesley Conservation Land Trust) and at the Wellesley Free Library. Author Katharine Fowler-Billings says the rock was named by Wellesley College geology students assigned to determine if the rock was “a smashed pinnacle or an outcropping of ledge.”
The rock gets mentioned here and there in town documents as well, including the Wellesley Comprehensive Plan from 2007-2017, in which Problem Rock is described as one of a number of “glacial erratics” in town that resulted from glacier movements. Problem Rock also rates a mention in the town’s Community Preservation Plan of 2008 as a notable open space attraction.
The Wellesley Conservation Land Trust says the age of the rock is now estimated at nearly 600 million years, in the Neoproterozoic period.
A Wellesley Townsman article from 1975 reports that that a granite marker was installed by the Hills Garden Club that year to recognize Problem Rock — a well-preserved marker located behind the rock and that you’d never realize was there if you weren’t looking for it (hat tip to local history buff Joshua Dorin for directing us to this article). Although apparently some people have a fondness for the marker and perhaps have even been toasting it, based on the empty beer bottles we found around it.
The marker reads: “Problem Rock — a Roxbury Conglomerate of the Permian Period Over 200 Million Years Old, Sometimes Referred to as Pudding Stone.”
According to an obituary for the Ruth Howe Tyler Smith of Needham, and formerly of Wellesley, she and her husband donated the land including Problem Rock to the Wellesley Conservation Council in 1974.