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Rock Formations and Features on Salt Spring Island

Updates and additions will be made as I collect more photos.

References are at the bottom of this page.

Spray Formation

66 to 67 million years old

250 – 300 m thick

This mud-stone layer underlies Long Harbour, continuing up the valley to Dunbabin Park. Being soft and easily eroded, it is usually covered by water or sediments. This photo was taken from Ontario Place boat ramp.


Northumberland Formation

68 to 70 million years old

200 m thickness

This mud-stone and fine-grained sandstone is the crumbly rock found at most the public swimming beaches around St Mary Lake.  It is the underlying formation of Bullock Lake, Bullock Creek and Duck Creek.  The photo was taken on North End Rd. at the North End of St. Mary Lake.


Cedar District Formation

70 to 72 million years old

250 to 350 m thick

This is a soft layer composed of sandstone and mud-stone.  It is typically covered by water or sediments. The Cedar District Formation underlays downtown Ganges, Vesuvius Beach and Madrona Bay.  It also forms the south shore of Ganges Harbour.  The photo was taken at Vesuvius Beach.


Pender (Ganges) Formation

75 to 80 million years old

200 m thickness

This mud-stone, silt-stone and fine-grained sandstone can be seen at Baker Beach.  It is the underlying formation of Booth Canal, Salt Spring Marina and Beddis Beach. The photo was taken at Baker Beach.


Haslam Formation

80 to 85 million years old

100 - 200 m thick

The Haslam Formation underlays an area running from Cushion Creek up to Cushion Lake and the Cranberry Valley  through to Bader's Beach.   It also sits beneath the sediments of the Fulford Valley.  It is composed of mud-stone, silt-stone and shale.  The photo was taken on the shoreline, 1 km south of Beddis Beach


Geoffrey Formation

67 to 68 million years old

400 – 500 m thick

This is probably the most widespread sedimentary rock on Salt Spring Island. This sandstone and conglomerate can be found on Scott Point, Nose Point, Eagle Ridge, Trincomali Heights, Channel Ridge and parts of Sunset Drive. The photo was taken at Welbury Bay Park, near the Long Harbour ferry terminal.


De Courcy Formation

70 million years old

300 m thickness

Sandstone of the De Courcy Formation can be seen at Southey Point and along Long Harbour Road between Upper Ganges and Quebec.  It is the dominant rock type from West Eagle Drive to Southey Point.  The photo was taken at Southey Point beach access.


Protection Formation

72 to 75 million years old

150 to 200 m thick

The Protection Formation is commonly seen on Salt Spring as its sandstone makes up Walker Hook, Grace Point, the Chain Islands and the points on both sides of Churchill Beach.  It can also be seen off Quarry Drive and the points on both left end of Vesvius Beach and left end of Beddis Beach. The photo was taken at Walker Hook.


Extension Formation

80 million years old

100 - 200 m thick

The ridge that runs from Mt Erskine to Mt Belcher is made of sandstone and conglomerate from this formation.  The photo below shows the sandstone component in Booth Bay and conglomerate from Mt Erskine. 

extension- Copy2.jpg

Comox Formation

85 to 90 million years old

100 - 200 m thick

The oldest layer of the Nanaimo Group, it is composed of sandstone and conglomerate.  This formation is visible at Beaver Point, Mt Maxwell and Russel Island.  Large conglomerate boulders from the top of Mt Maxwell can be found at Burgoyne Bay.  The photo shows sandstone at Russel with conglomerate from Maxwell (inset).

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