Here's why:

* Syncline: A fold in rock strata where the layers dip towards a common point, forming a trough-like shape. The youngest rocks are found in the center of the syncline.

* Anticline: The opposite of a syncline. In an anticline, the rock layers dip away from a common point, forming an arch-like shape. The oldest rocks are found in the center of the anticline.

Let me know if you'd like more information on folds in geology!