How did the physical geography of the north america influence british strategy for reaching quebec

The British managed to gain control of much of the eastern part of North America, but they didn't managed to do so with what is now Quebec. There are two basic reasons for this, one being that the French got there first and established themselves, and the second one being the physical geography.

The fact that the French got first to Quebec is crucial, as the invading force that would rich this area first would have had big advantage when it came to preserving the territory. Quebec has excellent location when it comes to defense. The coastline is shallow, so it is not really suitable for large invading ships to come directly on the shore. Apart from the water being the first defensive line, the area around the coastline is either frozen in the colder part of the year, or marshy in the warmer part of the year. After that second defensive line comes the third one, which are the Laurentian Plateau and the northernmost part of the Appalachians.

All of these factors combined made it almost impossible for the British to be able to conquer Quebec from the French, and it was only after the French left this part that the British managed to gain control of it.

the name of the theory is landmass theory.

where is the map at?