What is the correct term for a small pile of vertically balanced, water smoothed rocks?

What is the name for a small pile of rocks that are balanced vertically? I remember seeing these on the northeast coast of the U.S.A., generally at a beach. I remember being told many years ago that these were not properly called cairns, but that they had another name. I'm looking for that name. These may be associated with native Americans, but it has been so long ago that I cannot be certain that they are. I am certain that the name I am seeking is not cairn. Thanks.