 The mountains lie within the Basin and Range Province or Great Basin of the Western United States , which is characterized by a series of parallel fault blocks that form long north – south mountain ranges separated by wide , high @-@ desert valleys . The <unk> Creek Mountains are <unk> and <unk> blocks with steep <unk> along the southern and eastern sides of the range . The southern area of the range , known as The <unk> , has numerous <unk> of Cretaceous age granite . These granite <unk> are commonly found in the eroded valleys below the volcanic <unk> . 
