This doesn't seem to be the case. The authors are calling this the result of “Aeolian” forces (i.e the wind). They're claiming the wind blew dirt and debris into the cave where the extremely dry conditions preserved it.
Sortof windy in the cave, eh??? I don't find the part you mentioned, is there another article somewhere I haven't seen???
Anyway, it would seem to me the simpler the explanation, the better. I mean, since they're grasping for an explanation and all -- Occam's Razor and such. Someone else mentioned a rock fall/collapse that may have covered the turd in question. A side note, the area in and around Oregon is not exactly a desert, at least the present climate, so the "extremely dry" part doesn't seem to fit. I dunno; the whole thing smells.