James Hobin discusses the Roxbury Puddingstone that underlies so many parts of Boston, from how it was formed to its properties, which include being both remarkably tough and yet weepy.
Roxbury Puddingstone is underground but we can see outcroppings of it throughout Dorchester. Maybe there is a lump of it sitting in a friend’s backyard, or maybe there is a wall of it standing behind a row of triple-deckers, or maybe there is a slab of it leaning over the sidewalk near your house. A lot of times it is hidden by trees and undergrowth. And then there is the plain fact that it has been quarried, dressed, and set into buildings and walls all over town. Roxbury Puddingstone is the rock of Dorchester.
Ed. note: And of Hyde Park: There's a large outcropping on West Street, just north of Hyde Park Avenue and the Northeaster Corridor; not all that far from the Dell Avenue Rock, which is the remains of an ancient lava flow from the volcano we now know as the Great Blue Hill.