To remove the boulder:
Pick up stones, sticks and dried grass. They are all over the place except for the dry grass. It is close to where you climb up.
After the Scot says he'll help you and for you take off the log.
Go back up to the boulder.
Place the dry grass at base (trunk inserted under the boulder) of rock. In inventory, use the sticks with rock to get fire.
Use fire on the dry grass. The log will be removed.
Go back to the Scot. He can't leave because of the depressed Danika.
Walk around and see if you can find the Japanese woman that is with the lady from NY.
Bell will toll and you sleep.
The next day, walk around and talk to the German with the cap.
Find the Scot to help you and he can't.
Pick up more rocks and sticks. They are around.
Then go back to the gap and see the German prying the rock.
Help him. Up you go.