We're looking for a rugged, mountainous part of Scotland for today's Geo Quiz. This region was once covered by glacial ice sheets.

Scotland

Now it's considered one of the most scenic Scottish regions. It lies north and west of the Boundary Fault. That's a geologic line that divides Scotland into two distinct regions.

The northern portion is not densely populated overall. There are lots of mountains, valleys and lochs. As you might imagine, using mobile phones up there can be tricky. That's why many locals like to have good-old-fashioned phone booths around -- in case of emergency.

But British Telecom wants to pull the plug on some local pay phones.

We'll tell you why.

First, you've got to come up with the name of Scotland's more mountainous, northern portion.