The geology of the headlands jutting out from Rosario Beach consists of a suite of rocks known as "ophiolites". These rocks comprise oceanic tectonic plates. Two main components of the ophiolite are exposed here. First, as you approach the site from the beach on the west side of headlands, there are "ribbon chert" outcrops. The ribbon chert was formed on a deep-ocean abyssal plain as silica-based micro-organisms settled out of the water column, forming thick accumulations. Through a process known as "diagenesis" this micro-fossil graveyard was transformed into the very hard, silica rock known as chert. Pillow basalt, a second main type of ophiolitic rock, is exposed on the east side of the headlands. The pillow basalt was formed as magma was extruded into the ocean at a spreading center where two oceanic tectonic plates were moving apart. The pillow basalts form thick beds of tear-drop shaped rocks. The next logical question is, "How were these deep ocean rocks transported onto the continent and exposed at sea level at Rosario Beach?" Essentially these rocks were scraped onto the North American continental plate as the Juan de Fuca/Farallon oceanic plate was subducted beneath it. This tectonic activity accounts for why the ribbon chert rocks are so intensely folded and faulted.
A word of caution about rock hounding on these outcrops: Beware of the cliffs and drop offs in the area. These rocks are very resistant to erosion an so form some very steep topography. Children should be kept closely in tow. There are, however, many paths leading to cache area.
The geocache originally contained the following:
-An antique Honeywell SLR camera (may require some fine tuning)
-A pair of mini binoculars
-Geocaching sticker
-Green Man geocoin
-Malachite elephant statue
-Some books
-Other odd knick knacks
This park is fairly high traffic, please be discrete and hide the cache well after finding it.
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