The next phase in Death Valley’s development was primarily influenced by volcanic activity that spanned much of the Tertiary Period (65.5 - 2 million years ago.) As fault movement and mountain building stretched the land surface, the crust was weakened. Hot, molten material beneath the surface welled up and erupted at these weak points. The seething volcanoes first appeared to the northeast, in Nevada, and blanketed the Death Valley region with numerous layers of ash and cinders. The topography then consisted of gently rolling hills, perhaps simular to the present-day Skidoo area. Over time, the center of volcanic activity moved progressively westward, finally producing a chain of volcanoes from Furnace Creek to Shoshone, burying the ancient rocks of the Black Mountains. Secondary results of the ash and cinder eruptions include the vivid colors of the Artist’s Palette and Death Valley’s famous borate mineral deposits.