August26_2010

Botanical Glossary - Home - References Cited

Layer Cake Hill, sometimes called Layer Cake Mountain, is a volcanic land form composed primarily of Dacite [day-site] (volcanic rock with a high iron content). It shows unique layering that has not been seen anywhere else. Layering is expressed as thin layers separated by thick layers exposed along a weathered fault scarp. The compositions of the thick and thin layers are geochemically very similar. The thin layers represent veins generated during crystallization of the lava. The thin layers formed when the molten material contracted (shrunk) while cooling. Material was allowed to flow into the cracks formed by cooling. The material in the cracks further fractured when it cooled, and liquid material was allowed to enter the veins. The resulting rock was formed with a slightly different composition. The altered thin layers weather faster, thus visually showing the small primary chemical differences between thick and thin layers.

Approximately 50 million years ago, volcanoes erupted in the Kelowna area and along the Okanagan Valley. Since that time, erosion by large streams removed much of the volcanic bedrock, carving a broad deep valley along where Mission Creek now flows. The Ice Age eroded and carved the land by several glaciers during different times in the last one to two million years.

The last of these glaciers started to advance about 25,000 years ago and filled the valley higher than any of the mountains of the Okanagan today. It began to melt away about 15,000 years ago and finally disappeared about 10,000 years ago. As the Glacier melted in the Mission Creek Valley, the valley was blocked or dammed for some time by large blocks of ice and debris in Gallagher's Canyon. Material deposited from the ice served to partly infill the ancient valley. But lots of ice remained and the ice was still melting. This produced a lot of water. The water could not escape because of the ice dam in the canyon. Therefore, a large lake was formed along the upstream part of Mission Creek Valley. The flat topped terraces along the present valley sides were on the bottom of this ancient lake.

Water built up in the glacial lake behind the ice dam and finally the dam burst about 10,000 years ago, and a catastrophic flood occurred. All of this rushing and turbulent water was responsible for cutting a steep-sided gorge along the face of Layer Cake and eroding what we now call Gallagher's Canyon. One side (the north side) of this gorge was the steep face of Layer Cake Hill. The south side does not show this erosion effect because it was still covered with a thick layer of ice and debris.

During this time when the lake was being drained at a very high rate, high flows of melt water were also arriving here from the KLO Creek valley. The combination of these water flows must have created a huge whirlpool that swirled around carving out a portion of Layer Cake Hill and finally forming a pinnacle of rock that we call the "Pinnacle" today.

Photos - Views of Layer Cake Mountain and Pinnacle Rock from the Layer Cake Lookout. This is a well groomed, comfortable place with covered picnic bench and information kiosk to make a visit pleasant and informative. Looking from the upper Mission Creek Greenway Trail on the south rim of Gallaghers Canyon.

Photos - L-R - A close up of the interesting inflorescence of grass Agropyron Christatum (Crested Wheatgrass). This is a Russian native that is drought-tolerant and has been used in the past as a forage plant and been seeded for erosion control on dry, disturbed sites. It is a perennial bunchgrass with flat leaf blades hairy above, slender with claw-like auricles and short collar-like ligules. The inflorescence is the distinguishing feature of this grass. It has a crowded, flattened spike; spikelets spreading several times longer than the internodes. It looks like a fish bone about 2 to 4 mm in length. It is scattered and frequent at low to middle elevations in grasslands and roadsides.

Looking over at the north rim of Gallaghers canyon at a volcanic rock face.

Looking over the edge of the lookout area toward the southeast where you can see a cut in the hillside that is McCulloch Road.

Photos - Frame left: A little arrow shaped face of Ranunculus Acris (Meadow Buttercup) eyes and Anaphalis Margaritacea (Pearly Everlasting) head. Meadow Buttercup is a hairy perennial with one or several hollow stems. Leaves are heart shape in outline with deep lobes and divided nearly to its base, giving the hairy leaf a ragged appearance. Flowers are bright yellow in loose clusters at the terminal of hairy stalks. This is a European, weedy, introduced species that is now naturalized and widespread in scattered crops at low to middle elevations in moist meadows, roadsides and river banks. The juice of this plant is poisonous to cattle.

Frames right and center: Corylus Cornuta var Californicus (Beaked Hazelnut, California Hazelnut) close up of the beaked nuts and leaf. This shrub, or short tree only grows to about 4 meters in height and likes moist, but well drained sites (open forest with or without shade, thickets, rocky slopes, clearings or streamsides) in mid to low elevations. Leaves are alternate, elliptic with pointed tip and saw teeth - commonly flowers before leaves sprout in spring. The fruit are spherical in shape, with fine hairs covering a thin, husk covered shell - the lower end of the husk has a long projection, hence the name 'beaked hazelnut.' The beaked hazelnut is still a popular item for those who like to gather wild food. Natives in the past would gather the nuts in early fall to store for winter use (raw or roasted when fully ripe).

Click here for more photos of Gallaghers Canyon for this day.