They could and have before in the past. I was looking for some examples but while doing that, I also came across part of a book in Google Books that said that if a body is in cool, damp soil something called adipocere can slow down decomp and I seem to recall that the Vallecito area is/was at one point the site of a glacier. So it's probably very possible. I also think of miners (lots of mines in the area it seems too) and drifters of the past. People who stayed in town or died in town were buried in the town cemeteries, but drifters who died on the "road" were usually buried in unmarked graves along the way and it's likely nomadic Native American tribes wouldn't have designated burial grounds either.
I can't quote this article because it won't allow to copy the except but it should take you to that part on the link.
http://books.google.com/books?id=Eo... detect decomp for over hundred years&f=false
Also it appears that there is an archeological study regarding the use of HRD dogs in locating ancient burial sites.
http://www.k9forensic.org/human-signature.htm
and more on the Boca Cemetery project/history...
http://www.k9forensic.org/boca.html
The dogs are fascinating to say the least.
I wanted to respond also, in short to Seajay. I could see that they wouldn't want to panic people thinking there may be a predator out there when they didn't know just who the remains belonged to, especially since they were limited to what they could do at the time.