i already asked other internet resources. and noone knew. i cut one of the berries open and there were definitely rosa type seeds in there... but it's like 5-6 foot, bushy, red stems (sorry i dont think stem is a technical word), thorny, many rosehips.. they were deep red and smooth, now they are darker and shrivelly. full sun, mt. shasta, on the bank of a rivlet.. do my pictures suck? i can try again.
Yep, definitely a rose. The pics are not too bad (I've seen far worse posted here!); what would help most to identify the species is a pic taken a month or two ago, when it was in flower ;-)
Check through naturalised species, too - the leaves are fairly similar to some European rose species.
