Walk down a city street and you may pass disappeared oceans, mountains that rose and fell eons before humans evolved, and rivers that dried up millions of years ago and left their empty beds behind.
The stone that we use to build and decorate our cities is far older than the buildings and public art of which it is a part. Most of the rocks that make up the Earth's crust are tens to hundreds of millions of years old. If you can identify a building stone, you can get an idea of its history. If you happen to know where the stone came from, you can place it in its proper context in space and time, and discover the secret history of a marble floor or granite pillar.
| Sandstone
arch at Stanford University, Palo Alto California |
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BY E. Burns