MoapaPk wrote:

Marcsoltan wrote:These look like the kind of holes left behind after a large boulder is blasted into pieces by a dynamite. I have seen holes like these on canyon walls, rock formations next to a trail, and even on creek beds. If the explosive is not pushed all the way into the hole, what's left behind is a hole that doesn't go through the rock.

So far that seems most believable-- except it is odd that one is in a boulder with rounded edges...

Good point about the round edges. I think these holes could have had sharper edges to begin with. The original edges were fairly thin, in mass and volume, and probably already fractured from the force of the blast. Then, you add weathering, rain, stream, hot, cold, etc.etc.etc. I can see, in time all the edges become rounded.

Boulder Lake IS manmade, so I would also concur on the 'blasting' theory.

Sure is interesting that all the holes are in the center of each rock......

Wonder if the Master Blaster had somethin' to do with this ..

I don't know the answer to your question, but given the size and construction of the dam at Boulder Lake, I would guess these are remnants from the infrastructure used at the time it was built up.

That trail is between a dam and a reservoir, and I think what you see when you walk it is "that which hasn't been fully reclaimed by the forest" since construction of either or both bodies. I.e., there was likely a full-blown road in there at some point.

Ozark, please tell me this was not the highlight of your trip to McCall!

Grinding in its most elemental form involves rubbing two rocks together. The resulting abrasion finishes and smooths rocks into usable artifacts. North American Indians devised many types of specialized grinding tools designed for specific purposes. Hard-stone grinding tools were used to work softer metamorphic and sedimentary slate, shale and sandstone rock into artifacts.

yetibob3 wrote:Definitely blast holes, probably made by a portable rock drill as others have suggested. In the eastern Sierra back before 9/11 I frequently saw trail crews having more fun than on the 4th of July drilling rocks for blasting that 2 big guys ( or maybe 1) could have easily moved off the trail with digging bars; they had lots of military surplus tetrytol. A lot of these holes were never loaded, and are still to be seen. They also pinned rocks in place with sections of 1 inch rebar in drilled holes.

Those were also the days when the Inyo had people with blasting certs on staff. Those days are gone. If a rock comes down on the trail that can't be moved it's more likely the trail will get rerouted now than blasted (i.e. the Bishop Pass trail).