Metals-rich soils can occur naturally or through human activity, such as mining. Plants growing in metal-rich soils often incorporate metals into their tissues; the concentration of these metals varies, and plants which concentrate the metals most strongly are termed hyperaccumulators. Accumulation

Late Pinedale till deposits mapped in various stream valleys in the Comanche Peak Wilderness Area, north of Rocky Mountain National Park, indicate that Browns Creek Valley was glaciated from two directions simultaneously while the middle of the valley remained unglaciated. Till deposits at the upper