I decided to start a discussion on How the LBT dinosaurs were able to locate the Great Valley.
First of all, we know what the Narrator tells the audience at the beginning of LBT 1.
"Set out toward the West, searching for the Great Valley."
Next, consider what Littlefoot's Mother mentions to Littlefoot about where they are going:
"that is why we must walk as far as we can each day until we reach the Great Valley....and we must follow it each day to where it touches the ground."
The problems?
The Sun, as far as Science can say, has always risen on on side of the sky (the east) and fallen on the other (the west). If the dinosaurs were to always follow the Great Circle, they would end up walking back and forth in a rather humourous fashion.
Also, if the Sun is Due West (in the evening) of wherever a being is located, that would mean that the starting location is essential for this to work. If I were to start at point A and walk West, and you were to start at a significantly different Point B and walk West, we would not end up at the same destination.
for this reason, I feel that everyone who started on this "follow the bright circle quest" started from the same location. This explains partly why there are only so many dinosaurs in the Great valley; only those who were in the right location for this due West journey to take them there ended up there. Dinosaurs in other locations either didn't make the journey or ended up somewhere completely different.
This being said, were Littlefoot and his friends and family just lucky? Where did the Great Valley legend come from? How did they know that the Bright Circle would lead them there?