| Layne's butterweed grows in open rocky areas of gabbro and serpentine soils within chaparral plant communities. |
| The deepest layer is gabbro, coarse-grained but chemically equivalent to basalt, which forms when magma cools and crystallizes slowly. |
| Contacts between plutons of gabbro or hybrid rock and granite are commonly marked by net-vein complexes. |
| A soil of very close texture, the gabbro, is found, most largely in the north-east. |
| A dioritic pod in varitextured gabbro was sampled for U-Pb age determination. |
| The stones used include red jasper, white oriental alabaster, yellow chalcedony, and green gabbro. |
