Pale Limestone Ledge Above a Wide Valley

A reddish-brown boulder sits on a slope of flat, pale grey rock slabs in the foreground. To the left, a weathered outcrop of layered stone forms a rounded ledge. Beyond the edge, the ground drops into a broad valley with scattered dark evergreens and open, dry-looking ground. A tall, heavily eroded bank of grey slopes fills the middle distance, and farther back a long mountain range carries patches of snow beneath a clear blue sky. The light is even and cool, and the palette stays muted in greys, dusty blues and one warm rust note from the boulder.

The boulder is a glacial erratic, a rock carried by ice from somewhere else and left behind when the glacier melted. Erratics often differ in type from the bedrock under them, which is why this one stands out against the pale travertine of Terrace Mountain in Yellowstone National Park. Travertine is a form of limestone deposited by mineral-rich hot spring water. The wide, layered view suits a landscape-format desktop monitor, where the foreground rocks leave room for icons along the bottom edge.