Are these Indian Bedrock Mortars?

[ridger12]

A neighbor showed me these interesting rocks in the woods near my home. They are located in an area that is inaccessible to today's drilling machinery. The one mortar has the bottom missing from it, I am guessing from ice expanding in the hole and cracking the bottom out of the rock. I would appreciate any input from you artifact experts out there and thanks in advance for your assistance.

 

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[The Grim Reaper]

We need some better pictures. The close up are to close and the other pic has too many shadows. From what I can see though I would say it could be one.