James G. Moore David L. Jones 1973 <p>A Lower Jurassic ammonite has been found in metasiltstone&nbsp;of the Boyden Cave roof pendant, south-central Sierra Nevada,&nbsp;Calif. Although too poorly preserved to permit positive generic and&nbsp;specific identification, its general shape, coiling, and ornamentation are&nbsp;characteristic of Early Jurassic forms. Strata associated with the&nbsp;fossiliferous rocks in the pendant include quartzite, andalusite hornfels,&nbsp;and marble. This assemblage differs strikingly from nearby volcanic&nbsp;rocks to the east, some of which in the Ritter Range pendant also&nbsp;contain Lower Jurassic fossils. The presence of nonvolcanic Lower&nbsp;Jurassic rocks of the Boyden Cave pendant lying west of coeval volcanic&nbsp;rocks of the Ritter Range pendant is anomalous and may be the result&nbsp;of large-scale tectonic dislocations.</p> application/pdf en U.S. Geological Survey Lower Jurassic ammonite from the south-central Sierra Nevada, California article