Hmmmmm....

Well, that's a good question Crazy, but I don't think "obscure" is the right term. Both are pretty well known among serious Silver Age collectors.

I think that it would be fair to say that the White Mountain pedigree is vastly more wide ranging and of generally higher quality than the GR pedigree. I've seen more examples of early Marvels from the White Mountain collection than from the Green River collection.

What's nice is that both collections carry markers on them including date stamps and hand written dates (WM only), and are probably a little more protected from manipulation, pressing and resubbing for higher grades. It's easier to track both collections, although there isn't a White Mountain database online... yet.

Oh, if you made a list of the top Silver Age pedigree collections, I think White Mountain would make it into the top five, Green River would make it into the top ten list.

Hope that helps.