Granodiorite boulders inside Roxbury Conglomerate

On the South end of Hull, there are some really cool exposed outcrops of Roxbury Conglomerate. What is unusual about these exposed rock are the very large granodiorite boulders found inside the conglomerate (granodiorite is very similar to granite but tends to have more darker minerals) .

Below are pictures of some of the exposed conglomerate. Notice how large some of the boulders are that are included as pieces in the conglomerate - some are over a foot long. Can you think of conditions where such large boulders might be moved along and eventually deposited? Hint: click here for a current photo from Washington State.

Can you draw a picture that shows the type of environment under which the sediments that formed these rocks were deposited?