Last morning in Tongue, and Brian went for a walk. It is beautiful, perhaps the clearest morning yet. The oddly shaped mountains visible out the window have no fog around them today. The last three nights we had dinner and slept in an old building on the outside, modern inside.

We slept in the back, older part. Our view out the window included a ruined castle wall on a hilltop.

I was thinking last night about why we do this measuring folds and planes of stress in these ancient rocks. Does what happened here 3,000 to 1,000 (million years ago) matter today? Even in the late 1800’s, scientists recognized that some of the rocks on one side of a big fault looked more like rocks in North America than the rocks on the other side of the big fault. That is fascinating and fun, but important? All I know is that understanding these things makes me feel more human. Perhaps it is similar to how an artist feels, or a musician. I learn geology, because it completes me.

Later….

The two stops were both at beaches. The first one, on the North Sea, 400 conglomerate sits on top of the 1000 gneiss rocks.

The cobbles in the conglomerate are rough, not rounded. We walked along the beach a bit to see the contact between these better. Yes, that is Brian off to the right.

Then we drove to the Moray Firth, the giant elongate bay along the Great Glen Fault, which is also the fault that Loch Ness is on. We looked at grey sandstones that had cool fracture systems related to faulting about 400.

The drive to Inverness was uneventful. We said goodbye to our new friends, were dropped off at the train station and continued to Glasgow.

What does this mean? How heavy can a plant get?

• Scotland Geotrip