Thursday, 13 June 2019

CRETACEOUS CAPILANO RIVER

Cretaceous Plant Material / Three Brothers Formation
Vancouver has a spectacular mix of mountains, lowlands all wrapped lovingly by our deep blue Pacific. When we look to the North Shore, the backdrop is made more spectacular by the Coast Mountains with a wee bit of the Cascades tucked in behind.

If you were standing on the top of the Lion's Gate Bridge looking north you'd see the Capilano Reservoir is tucked in between the Lions to the west and Mount Seymour to the east on the North Shore. The bounty of that reservoir flows directly into your cup! If you look down from the reservoir you'll see the Capilano River as it makes it's way to the sea.

The Capilano River on Vancouver's North Shore flows through the Coast Mountains and our coastal rainforest down to the Capilano watershed enroute to Burrard Inlet. The headwater's are at the top of Capilano up near Furry Creek. They flow down through the valley, adding in water from rain, snow melt and many tributaries before flowing into Capilano Lake. The lake in turn flows through Capilano Canyon and feeds into the Capilano River.

The Capilano River's path, water levels and sediment deposition have been significantly altered by our hand.

We have Ernest Albert Cleveland to thank for much of our drinking water as it is caught and stored by the dam that bears his name. It was his vision to capture the bounty from our watershed and ensure it made its way into our cups and not the sea. Both the water and a good deal of sediment from the Capilano would flow into Burrard Inlet if not held back by the 91 meter concrete walls of the Cleveland Dam. While it was not Ernest's intention, his vision and dam had a secondary benefit. In moving the mouth of the Capilano River he altered the erosion pattern of the North Shore and unveiled a Cretaceous Plant Fossil outcrop that is part of the Three Brothers Formation.

The fossil site is easily accessible from Vancouver and best visited in the summer months when water levels are low. The level of preservation of the fossils is quite good. The state in which they were fossilized, however, was not ideal. They look to have been preserved as debris that gathered in eddies in a stream or delta.

There are a mix of Cretaceous species found only in the sandstone. You will see exposed shale in the area but it does not contain fossil material. Interesting, but again not fossiliferous, are the many granitic and limestone boulders which look to have been brought down by glaciers from as far away as Texada Island. Cretaceous plant material (and modern material) found here include Poplar (cottonwood)  Populus sp. Bigleaf Maple, Acer machphyllum, Alder, Alnus rubra, Buttercup  Ranvuculus sp., Epilobrium, Red cedar, Blackberry and Sword fern.

From downtown Vancouver, drive north through Stanley Park and over the Lion’s Gate Bridge. Take the North Vancouver exit toward the ferries. Turn right onto Taylor Way and then right again at Clyde Avenue. Look for the Park Royal Hotel. Park anywhere along Clyde Avenue.

From Clyde Avenue walk down the path to your left towards the Capilano River. Watch the water level and tread cautiously as it can be slippery if there has been any recent rain. Look for beds of sandstone about 200 meters north of the private bridge and just south of the Highway bridge. The fossil beds are just below the Whytecliff Apartment high rises.