Nice finds. I always enjoy finding old marbles and have found many of different kinds. Here is some information about Bennington marbles. This was copied from Marblecollecting.com.
"Bennington marbles are a type of glazed clay marble. They are not very dense. The marbles are fired clay with a salt glaze on them. Benningtons are readily identifiable by both their coloring and the little “eyes” that they have on them. These are spots where the marbles were touching each other while they were being fired, resulting in those spots being uncolored and unglazed.
The term “bennington” is actually a misnomer. There is no evidence that they were ever made in Bennington, Vermont, or that they have any lineage to the Bennington pottery that they resemble and from which they get their name. It appears that all Bennington marbles were imported from Germany. Some boxes have been found that contain them and that are labeled “Agates - Imitation / Made in Germany.”
Benningtons are usually colored brown or blue. Green or black Benningtons are rarer. Marbles that have both brown and blue on them, as well as a little green, are referred to as “fancy Benningtons”. These are rarer than the single color variety. There are also some very rare examples with pink on them."
