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Rock Formations

Felsenmeer Slope

Felsenmeer slope. View other habitats.

Rock formations are found primarily in higher elevations of the upper watershed.

Talus and Felsenmeer

Talus and felsenmeer are prevalent on steep slopes north of Findley Lake and on the south-facing slopes of Tinkham Peak.

Talus is the accumulation of broken rock that has fallen from above, and thus usually forms slopes on steep mountainsides or at the bases of cliffs.

Felsenmeer translates from the German as “sea of rock”: exposed rock that has been broken by freeze/thaw action into angular rock rubble covering large slopes. The continuity and depth of felsenmeer vary with climate, vegetation, and rock type, but can be as much as 4 meters (12 feet) deep overlying solid bedrock.

Cold, moist air travels within and out of this rock rubble, which affects the plants and animals that use these habitats. For most plants, broken rock is a poor rooting and growing substrate, so talus and felsenmeer often lack well developed woody vegetation.

However, a diverse moss and lichen flora often dominates the plant communities found on talus and felsenmeer. The moss group Rhacomitrium (grey frayed-cap mosses) is particularly adapted to the harsh existence of living on solid rock.

Sometimes forest stands become established, consisting of:

  • Douglas-fir (Pseudotsuga menziesii)
  • mountain hemlock (Tsuga mertensiana)
  • subalpine fir (Abies lasiocarpa)

Shrub communities are also found, usually dominated by:

  • vine maple (Acer circinatum)
  • mountain-ash (Sorbus spp.)
  • slide alder (Alnus sinuata)

Rock Outcrops and Cliffs

Rock outcrops and cliffs are present in Seattle Creek, in the upper reaches of Rack Creek and the Rex River, and above Rattlesnake Lake.

Rocky summits and sheer rock walls are found in the glacially carved U-shaped valleys and cirques of upper Goat Creek, Troublesome Creek, and Findley Lake basins.

Basalt cliffs with columnar jointing are found in the upper reaches of the Rex River.

These rock-dominated habitats challenge plant life by offering poor and eroding rooting surfaces as well as extreme climatic exposures—but, plants do find their way there.

Plant species well-adapted to cliffs and rocky summits include:

  • beardtongues (Penstemon species)
  • Indian-paintbrush (Castillejia miniata)
  • common juniper (Juniperus communis)
  • Pacific yew (Taxus breviifolia)
  • stenanthium (Stenanthium occidentale)
  • Oregon spike-moss (Selaginella oregana)
  • bluebell bellflower (Campanula rotundifolia)

Habitat types in the watershed: