(Iron-cemented conglomerate)

Puddingstone looks like a person took a bunch of small, smooth rocks, mixed them up with some concrete, then let it all harden together. But the rock you see here was not made by any person. Puddingstone is a conglomerate rock, consisting of several kinds of rock mixed together and cemented by a natural matrix.

There are several kinds of puddingstone. The kind we have in Newton is called Roxbury conglomerate. It forms the bedrock underlying most of our city of Newton and nearby Boston. It is named for the part of Boston called Roxbury, because that is where early settlers saw impressive examples of it.

Roxbury puddingstone was created about 580 million years ago. Glaciers moved the cobblestones, tumbling them around and around until they were smooth and rounded. These pebbles, mostly granite and quartz, settled in sand. For millions of years the pebbles and sand were pressed together until the mixture became stone.

This stone was used in the construction of walls and houses in Newton and Boston and you can even see it in the foundations of some Boston churches.

Just to your left is a tree trunk lying on the ground covered with turkey tail fungus.



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