In Monster Rancher 3, a lone tree sits near the end of the area, and a valley splits the middle (probably the same valley that Jill finds the frozen Phoenix in). Maya's family owns a large portion of the area, and she allows you to use it for training.
The large open expanse that covers most of this area is called the Brillia Snowfield (it is one of the ranch locations offered in My Monster Rancher). The snowy peak rising in the back (Mt. Kyrus) is the highest peak of the Papas Alps and also where Moo finds his ancient body frozen in the anime series.