What kind of shelter did Brian make in Hatchet?

Brian makes a shelter up against a stone ridge. 

After the plane crashes, Brian realizes right away that he is going to need some kind of shelter.  His windbreaker is torn to shreds.  He is also at the whim of the wild animals.  Brian finds his priorities almost immediately. 

He had to have some kind of shelter. No, make that more: He had to have some kind of shelter and he had to have something to eat. (Ch. 5) 

Although Brian may be just a kid on his own, he does have some small measure of survival knowledge.  He remembers playing the park with his friend Terry and deciding that the best shelter in the wilderness would be a lean-to.  Brian decides that it is a good idea for him too. 

His eyes fell upon the stone ridge to his left and he thought at first he should build his shelter against the stone. But before that he decided to check out the far side of the ridge and that was where he got lucky. (Ch. 6) 

Brian uses the sun to determine that the far side of the ridge is the northern side.  The overhang makes an almost perfect roof for Brian.  It is the next best thing to finding an actual cave.  Brian is too weak to make proper walls, however.  Remembering a program about air force pilots taking wilderness survival training, Brian decides to look for berries. 

The gut-cherries were a bad idea, but the shelter works well.  Brian starts to think of it as home, and works to make it more comfortable and secure.  Little by little he gets strong enough to build on it. 

The brush made a fair wall, not weather tight but it cut most of the wind off. He hadn't done so badly at that. Maybe it wasn't much, but also maybe it was all he had for a home. (Ch. 7) 

Brian’s shelter is invaded by a porcupine, but generally makes him feel safe.  He decides to add a fire, and after some trial and error manages to get one going.  Brian is really surviving on his own.