Concretions in the Champlain formation of the Connecticut River valley were noted by the earliest settlers in the region. The concretions were found in great numbers among the gravels of the Connecticut River and its tributaries, and on and in the thinly banded beds exposed at low water. The name “claystones” was early applied to them, a name that was significant because the concretions were harder than the clay enclosing them. Later, the term “clay-dogs” was given them by the workmen in the brick yards, perhaps because of the persistence with which the forms appear with the clay, or it may have been an opprobrious term intended to convey the idea that the concretions were nuisances in molding the brick.
The concretions occur in an infinite variety of forms, but the most striking feature, to which the writer's attention was called in 1910 by the late R. D. Salisbury, . . .