You spin.

Heads; tails it is." "Then I will choose the mouth here.

You go up to the mouth's head." "Don't you be walking about when you get to the top," Dave said.

"Find some place where you can get a clear view all round, and then lie down.
Choose a bit of shade, if you can find it.

When we knock off work and have had a bit of grub, I will come up and take your place." It was just getting dusk when Dave came up and relieved Dick.
"Are you going to stay here all night, Dick ?" "Yes, we have agreed I shall keep watch here to-night, Boston to-morrow night, and then I go on again.