Hi Jack.....are you sure it's Mauregan Arms or could it be Wauregan Arms (with a "W" instead of an "M")?
Wauregan Arms is one of the 150+ names under which Crescent Arms of Norwich, CT, made shotguns. (And, incidentally, Wauregan is the name of a small town in CT, about 12 miles south of Norwich, between Norwich and New London
If it is "Wauregan", if it has proofmarks, it was made in Belgium. If no proofmarks, it was made by Crescent.
Crescent was in business from 1888 until about 1930, and was the largest maker of "Hardware Store" shotguns in the U.S. with a large variety of tradenames. They also made a small number of higher grade shotguns under the Crescent brand.
Despite that fact that Crescent made most of it's "hardware store" shotguns to sell at a fairly low price, I've never seen a Crescent made shotgun (under whatever tradename) that wasn't
a decently made gun and a good value for the price.
If this is a Crescent made "Wauregan", I'd value it a bit higher than Tex.....say from $50 to $100 (but, then again, I have a soft spot in my heart for these old Crescents
BTW.....this gun was most likely built in the blackpowder era, and shouldn't be used with modern smokeless powder shotgun loads. If you want to shoot it, take it to a good gunsmith and have it checked out.
And.......while it may not have a high $$$ value, if it belonged to your Great-Great Grandfather, it's a family heirloom and therefore priceless! Keep it and pass it down to your children and grandchildren.