Castle Crags State Park is within the Klamath Mountains geomorphic province. The eastern Klamath Mountains are built from the oldest rock in the range with the newest to the west. This is due to the continued accretions of oceanic crust added on to the western edge of North American continent. Rocks surrounding Castle Crags are mostly of the Ordovician-aged (443–490 million year old) Trinity ultramafic sheet.
Venturing east on Highway 299 from Humboldt Bay, a stark transition–rarely noticed by travelers–occurs at Berry Summit (2900 ft). Leaving the Coast Range and entering the Klamath Mountains the landscape becomes defined by varied, complex rock types. One of these unusual rock types is known as ultramafic rock or more commonly as Serpentine. In North America, serpentine rock appears at the Earth’s surface most frequently in northwest California. The Horse Mountain Botanical Area (HMBA) is a celebration of the rock and climate that interact to create unique high elevation plant communities. In coastal northwest California, spring has arrived. Allison and I did not want winter to pass us by–we were ready for some snow play. Packing our snowshoes and lunch, we drove to the snow of the HMBA in the Klamath Mountains in less than an hour.
Gaining an understanding of geology and fire ecology
I had often pondered a high and extensive ridgeline in the middle of the Trinity Alps Wilderness from other mountain top vantage points on which I stood–at one point or another–in my adventures in the Klamath Mountains. It took me several years to realize this jagged range had its own name and many years more to actually get to this isolated place. Finally, in October, I climbed my way into the high country known as Limestone Ridge. I had read this extensive ridgeline (over 3 miles long) was one of the best examples of Karst topography in western North America. This summer, the spectacular Marble Mountain was my first introduction to Karst limestone landscape in the Klamath so I assiduously pursued a chance to see more. With those distant images and arresting words burned on my brain I was finally climbing–up–up–up–from Hobo Gulch in the Trinity River Canyon.