Blanchard Mountain was once covered in a massive sandstone deposit called the Chuckanut Formation. Over time, this sandstone unit grew to be more than 10,000 feet thick, trapping many fossils of ancient plant and animal species.

geology of

Great Slave Lake (Wikipedia) Great Slave Lake is the second-largest lake in the Northwest Territories of Canada (after Great Bear Lake), the deepest lake in North America at 614 m (2,014 ft), and the tenth-largest lake in the world by area. It is 469 km (291 mi) long and 20 to 203 km (12 to 126 mi) wide. It covers an area of 27,200 km2 (10,500 sq mi) in the southern part of the territory. Its given volume ranges from 1,070 km3 (260 cu mi) to 1,580 km3 (380 cu mi) and up to 2,088 km3 (501 cu mi) making it the 10th or 12th largest by volume.

Oyster Dome (wa100.dnr.wa.gov) Take an invigorating hike up Blanchard Mountain, located south of Lake Samish, to the geologic treasure known as Oyster Dome—a rounded, rocky promontory with spectacular views of the San Juan Islands and the Olympic Mountains. Oyster dome is located in the 4,500-acre Blanchard State Forest, the only place in Washington where the Cascade Mountains meet the Salish Sea.