Broad areas of folded rock layers that resemble an upside-down bowl are called synclines.

Here's a breakdown:

* Syncline: A fold in rock layers where the youngest rocks are in the center of the fold, and the layers dip downwards on either side, resembling a trough or a bowl.

* Anticline: The opposite of a syncline, where the oldest rocks are in the center and the layers dip upwards on either side.

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