evidence for in sediment layers, the other being the dino-destroying rock that hurtled into the planet 65 million years ago. The second impact took place 12,900 years ago at the onset of an unusual cold climatic period called the Younger Dryas. [this remark is a surprise to myself - Arclein]
He immediately found one tusk with the tell-tale pockmarks and asked the trading company if he could look through its entire collection. He sorted literally thousands of items.