As indicated by the name, the ophiolite is defined by the presence of ultramafic rocks in the California Coast Ranges.
Where it is exposed, it generally underlies the various sedimentary rocks of the Great Valley Sequence, and may be coextensive with the contemporaneous (but slightly younger on average) Franciscan Assemblage, as would be expected by an observational application of the law of superposition.
[1] The Coast Range Ophiolite is characterized by obduction of oceanic crust onto land.
[2] Most of the rocks in the ophiolite were part of an accretionary wedge on the continental margin of Laurasia that was thrust onto land during the Jurassic through the influence of subduction.
[3] The exact origins of the rocks found in the ophiolite are a matter of debate; some geologists hypothesize that the rock primarily consists of mid-ocean lithosphere, while others assert different ideas related to island arc terranes associated with the Nevadan orogeny.