The Franciscan Complex or Franciscan Assemblage is a geologic term for a late Mesozoic terrane of heterogeneous rocks found throughout the California Coast Ranges, and particularly on the San Francisco Peninsula. It was named by geologist Andrew Lawson, who also named the San Andreas fault that defines the western extent of the assemblage.
Chevron folds in ribbon chert of the Marin Headlands, California. Geologist Christie Rowe for scale.
Shale matrix mélange with clasts of sandstone and greenstone on Marshall's Beach, San Francisco
Ribbon Chert of the Marin Headlands Terrane, exposed at Marshall's Beach, San Francisco.
Pillow structures preserved in greenschist-facies metamorphosed basalts of the FranciscanComplex, Black Sands Beach, Marin Headlands, California. Field of view is approximately 2 m wide.
Andrew Cowper Lawson was a Scots-born Canadian geologist who became professor of geology at the University of California, Berkeley. He was the editor and co-author of the 1908 report on the 1906 San Francisco earthquake which became known as the "Lawson Report". He was also the first person to identify and name the San Andreas Fault in 1895, and after the 1906 quake, the first to delineate the entire length of the San Andreas Fault which previously had been noted only in the San Francisco Bay Area. He also named the Franciscan Complex after the Franciscan Order of the Catholic church whose missions used conscripted Native American labor to mine limestone in these areas.
Lawson c. 1922
