The Griffo's and Griffons are a great place for you to level up from 41 - 42. All of the Griffo's con neutral to you meaning they will not attack you unless you attack them. Also the little Griffo's have two green dots meaning they are much easier for you to kill then a normal mob. Aside from the Griffo's and Griffons in this area you will also find Daru's and Crookhorns for you to kill that are also Neutral and have two green dots.
Another upside of this area is that if you've been raising your Extract Vitality Skill you will find tons of Anathe Fiber in this valley. Anathe Fiber is used by Tailors in making some of the best cloth and leather armor in the game. Also this area is very safe compared to the other ones because there is no Rift that drops Elyos out nearby.