View Single Post
Old 10-27-2013, 01:48 PM   #81
PaulGir
Adventurer
 
Joined: Dec 2009
Oddometer: 52
[QUOTE=UltiJayne;22165574]


An exhibit outside the national museum. They've found a lot of these perfectly formed rock spheres in Costa Rica. Not really sure who made them or why.
These are concretions.They form under water.We have some in NZ too.

http://en.wikipedia.org/wiki/Concretion

PaulGir is offline   Reply With Quote