Ancient heights

Leaf fossils can help track the rise and fall of mountain ranges.

By Emily Sohn, 00:00 AM December 17, 2004

Pores that take in carbon dioxide appear in this microscopic view of a present-day California black oak. The sample was stained orange so that details would be more visible.

You probably know where all the hills are in your neighborhood. Even so, the planet hasn't always had the same lumps. In some places, Earth was even lumpier that it is now. In other places, it was smoother. Over millions of years, entire mountain ranges have come and gone. The landscape is always changing.

Now, a geologist from the Field Museum in Chicago says that she has found a new way to figure out how the shape of Earth's surface has changed over time. Her strategy? Leaf peeping.

A tree's ...

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