Need help with my mystery rock origin.

[Downunderwonder]

So, I'm completely wrong. What's the correct answer?

No. You're dead on, just I am surprised most of that isn't common knowledge among bass players.

 

[Stewie26]

It's hard to judge the size from the Pics but a rock that big should weigh more than 40 Lbs. More like 200.

Actually, the size of the rock just a little bit bigger than a bowling ball. I am estimating 40 pounds or so. I know it weights a little more than my 35 pound dog.

 

[Tom Bomb]

I imagine you may have a very old millstone of some sort there -

Not that I'd know


A thing of beauty it is. Here's a Merry Christmas Millstone

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[T_Bone_TL]

Could be it is natural (the sediment lines do strongly suggest that), but came to be where it is by having been used as the weight on the bottom of a fishnet, due to the convenient natural hole. Then again, glaciers dumped all sorts of rock all sorts of places far from where it started without the intervention of people.

 

[FunkHead]

Actually, the size of the rock just a little bit bigger than a bowling ball. I am estimating 40 pounds or so. I know it weights a little more than my 35 pound dog.

I believe you. Does your dog have his drivers license? Looks like a millstone could be the answer but it'd be cool to know for sure.

 

[bolophonic]

That is so completely awesome.

 

[ZenG]

It could be a 'sounding' rock. Used by ancients to tell how deep the water is.

 

[TOOL460002]

The alternating layers and smoothness does seem to indicate natural (I like the log idea). Is there any wear on the inside of the hole that would indicate a rope was put through It? And is it soft sediment sandstone type stuff? Looks that way in the pic.

I don't know of any animals that would burrow in that type of rock all the way through, so probably not that. Probably natural. But could be natural, found, and reused as a boat anchor. There are tons off California from Asian shipping up to the 1900's for sure, probably even up to WW1 or so.

There were a lot of those anchors and they were used for hundreds of years all over the world. The hole looks more natural than formed for an axle, so I sort of doubt the mill stone idea. And why make a mill stone out of soft stone?

I vote natural. But with the possibility of being used as an anchor out of opportunity. Although it wouldn't be that heavy of an anchor I don't think. Hmm... Maybe just natural.

 

[Downunderwonder]

Sometimes a pie plate is a frisbie but 99.999% of the time it's just a pie plate.

 

[TOOL460002]

Sometimes a pie plate is a frisbie but 99.999% of the time it's just a pie plate.

Agreed. It's a nice thought/story, but, yes, I think this pie plate is natural. But very cool.

 

[Aberdumbie]

My first thought was a millstone. Not unusual to see them in people’s yards around here. But it wouldn’t make sense being relegated to the ocean. Whatever it’s origin it sure looks cool!

 

[RoadRanger]

"Never let the truth get in the way of a good story" - Mark Twain

 

[Oddly]

I'm thinking a millstone too.
Have any drummers been reported missing in your area?

Probably some band got tired of theirs, took him out on a little cruise, tied that around his neck and solved their problem.

 

[hbarcat]

We can rule out 3 possibilities:

1) It was not deposited by a glacier. It was found in southern California and the glaciers never got anywhere near that far south.

2) It was never used as a millstone. Millstones must be very close to perfect circles in order to function. This stone is grossly oval shaped.

3) The hole was not made after the stone was formed. It's clear the layers of sediment that make up the stone were formed around the hole because they bend around it.

 

[Stewie26]

The Chinese anchors off Palos Verdes, CA where originally discovered by a guy named Bob Meistrell of Redondo Beach, CA in the 70's. He went on to co-found a company called, "Body Glove" which some of you may recognize, and made a fortune. The Chinese anchors he found were just a few hundred yards offshore where I found this rock. I am agreeing with TB poster, DownUnder. The more I look at the rock, I am thinking the hole was made by nature. With that said, the rock is a much different composition than other rocks from surrounding area. Perhaps the rock was formed by nature somewhere else, found by mariners and then used for securing fishing nets or a small boat. The more I research this, the more I see that there may be some credibility that the Chinese may have been in North America long before the Europeans. This Link is interesting [Invalid or Expired Link Removed]

Also, Youtube

 

[LBS-bass]

The alternating layers and smoothness does seem to indicate natural (I like the log idea). Is there any wear on the inside of the hole that would indicate a rope was put through It? And is it soft sediment sandstone type stuff? Looks that way in the pic.

<snip>

I vote natural. But with the possibility of being used as an anchor out of opportunity. Although it wouldn't be that heavy of an anchor I don't think. Hmm... Maybe just natural.

It may also have been used to anchor something smaller than a boat, like a fishing net or something. I also think it's natural but certainly it could have been put to a purpose.

 

[ahc]

Talk to a geologist. You should be able to find one at a local university. But until then...

 

[Pilgrim]

I think it was imported to that spot. I suspect it's too big to be a weight for a net, but remember that sailing ships carried rocks as ballast, and from time to time they might have dumped ballast if they had loaded more cargo than planned and needed to reduce weight. Dumping ballast rocks overboard would not have been unusual.

 

[Tom Bomb]

Quite the hot topic for such a cool stone I've had a little dig to see what's on offer by way of an explanation. Learnt a new word - quern - always a red letter day So thanks Stewie There's little doubt, I'd have lugged that rock up the cliff, had I been in your shoes. It's such a lovely artifact. The imagination runs wild.

There's no reason sedimentary rock should be ruled out, for its use as a millstone, or a quern-stone,

The best type of stone from which to manufacture quern-stones are igneous rocks such as basalt. These have naturally rough surfaces, but grains do not detach easily, so the material being ground does not become gritty. However, such rocks are not always available, meaning that quern-stones have been manufactured from a wide variety of rocks, including Invalid Link Removed, Invalid Link Removed and limestone.
Quern-stone - Wikipedia

There's also no need for a millstone to be perfectly symmetrical though the constant wearing away of upper and lower stones would seem to favour greater symmetry eventually and should have led, I imagine, to further innovation and advances in milling, as time marched on.

from Centre for Digital Scholarship Journals​

Here's another to flesh this out,

from Beautiful Neolithic and Iron Age querns from Norway. On the history of grinding grain
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These things can be ancient - rock lasts so long and, over time, can take on so many different forms. We have stone here formed by nature over millennia by humic acid which eventually eats great monolithic holes in solid rock.

These, and similar circumstances, would produce perfect quern-stones, and I'd guess, they probably have We're a clever bunch.

As to the anchor, ballast and fishnet theories, a little fossicking in the histories turns up very little of substance to corroborate them. Just imagine why throwing such a practical and rare stone overboard might be considered foolish when there were so many boring old rocks around that would do the same job From what I can tell, these kinds of items would've probably looked more like this,

https://image.slidesharecdn.com/evo...tion-of-roman-anchors-4-638.jpg?cb=1351865247​

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It's also worth noting that, over time, coastlines have shifted considerably. What was once land's end may now be many miles offshore. Some of these clusters of underwater objects could well have once been at the edge of oceans, cast away, and barely submerged at all. We still do this today - dump stuff off the coast. Very civilized

Great thread. Good luck with this adventure y'all -

popping corn at the ready, just in case the grinding idea fails to flower and the bottom drops out of the miller's tale

 

[Snakeman1066]

The wife and I recently visited a beach in California @ Montana de Oro and found literally 100's of rocks very much like yours in various shapes and sizes. some as small as a quarter and some as large as bowling balls...all with a single hole perfectly formed in the middle...I ended up bringing quite a few home myself...

They guy I showed mine to was sure that the holes were created by either Strongylocentrotus purpuratus or by piddocks YMMV