I love beach glass and I have been wanting to write a post on it. My dad lives on the southern shore of Lake Erie and as you describe back in the day the cities along the coast of this Great Lake would haul trash on barges a few miles off-shore to dumping grounds and now these sand and water worn pieces of colorful refuse have returned to us.
Finding a piece of beach glass along Erie's shore is much harder than what is shown in your picture. An hours worth of beach-combing might net you a handful. My dad is retired so he has spent many hours walking the beach and has accumulated quite a large collection.
Because the nation's railways have to skirt the Great Lakes many tracks pass through Northern Ohio. A railroad runs past my dad's place then runs along the lakeshore for a few miles. Last year I was able to identify many pieces of pretty aqua-marine colored sea glass in his collection as broken shards of antique insulators undoubtedly chucked into the lake when lineman serviced the telegraph wires along the railway. Several larger hunks still show the thick threads which positively identifies them as a piece of a screw on glass insulator.
Nice job and thanks for sharing your trip. I am enjoying it for sure.