| Answer | Crossword Clue |
|---|---|
| SESAME | Oldest known oil source |
| COD | Source of a well-known oil. |
| SUMERIAN | World's oldest known civilization. |
| ARLON | Oldest known city in Belgium |
| SEASHELLS | Oldest known form of currency |
| archaeopteryxes | The oldest known fossil bird, of the late Jurassic period. It had feathers, wings, and hollow bones like a bird, but teeth, a bony tail, and legs like a small coelurosaur dinosaur |
| archaeopteryx | The oldest known fossil bird, of the late Jurassic period. It had feathers, wings, and hollow bones like a bird, but teeth, a bony tail, and legs like a small coelurosaur dinosaur |
