11-1/2" Utah Septarian Bookends Agate Bookends The oldest blastoids lived about

The oldest blastoids lived about 425 million years ago

From the Latin word "citrus / citron tree"

Some Megalodon teeth have been measured over 7" in length

low and heavy heads

At the time

11-1/2" Utah Septarian Bookends Agate Bookends The oldest blastoids lived aboutThese strange and handsome Geodes are from the Henry Mountains of Utah. Originally formed in an ancient sea floor some 50 70 million years ago, sediment collected around sea life as they decomposed, forming a concretion. Calcium carbonate from the shells of these creatures began to take a new form over time, creating calcite crystals and bands of aragonite. As the oceans receded, these mud balls hardened, shrinking and cracking in the sun. The gold