For those open to the possibility of stone softening as a means to explain the existence of the various older megalithic structures, something occurred to me.
If it were easy enough to mold and shape and 'relax' stone shapes into their present improbable forms, would it not be relatively easy to create a hollow corner stone to contain information about he builder, time frame, or any other items contained in a time capsule?
If there were ancient advanced civilizations aware of the fragile state of humanity after a cataclysm, and as a result, were focused and intent on leaving important information for future civilizations, then given the possible technology to soften stones, wouldn't making hollow stone time capsules be both easy and possibly the best way to protect artifacts to pass along to a future advanced civilization?
If I put myself in the hypothetical shoes of a past remaining group from an advanced civilization, and I presume I have some technology to soften stone, it seems like a no brainer to make it policy, and tradition to create a few hollow corner stones that contain important information. Considering many of these structure have proven to be able to survive multiple millenia of earth moving cataclisms, its potentially the safest place to put that stuff.
I"m not up on the specifics of technology available today to scan individual blocks for voids, but if it can be done without the fear of damaging the stone itself, it might be easy to gain permission to do so. I'd be interested to see what we could find.
Bottom line and my main point is - given the above suppositions, wouldn't you consider rock void time capsules a obvious means to protect important info? Even if it were a redundant back up to some other as yet uncomprehended messages in the sacred numerology, or star maps in the architecture, etc. I can't imagine why they wouldn't.