QUESTION:
Yogi keeps being mentioned on TV as being "water worn," yet it looks to me
like a typical volcanic bomb. Which one is it?

ANSWER from Wendy Calvin on July 28, 1997:
I think the only real evidence that the rocks around the Pathfinder site
have been transported by water, and hence should be water worn, is the
Viking regional images showing streamlined islands and other features
suggesting past flooding action by water.

To my knowledge there is no surficial evidence yet from the rocks themselves
that can really distinguish water vs. volcanic or impact ejection as origins
of the rocks.