Big Marbles............

Just click on picture to see fullsize.

Sent from Marion B.

"The Moeraki Boulders are huge spherical stones that are scattered over the sandy beaches, but they are not like ordinary round boulders that have been shaped by rivers and pounding seas. These boulders are classed as septarian concretions, and were formed in ancient sea floor sediments. They were created by a process similar to the formation of oyster pearls, where layers of material cover a central nucleus or core. For the oyster, this core is an irritating grain of sand. For the boulders, it was a fossil shell, bone fragment, or piece of wood. Lime minerals in the sea accumulated on the core over time, and the concretion grew into perfectly spherical shapes up to three metres in diameter.
The original mudstone seabed has since been uplifted to form coastal cliffs. Erosion of the cliffs has released the three tonne captive boulders, which now lie in a haphazard jumble across the beach. Further erosion in the atmosphere has exposed a network of veins, which gives the boulders the appearance of turtle shells."

From New Zealand. Thanks again Marion.