| Substrate Origin | Geologic Substrate |
| Substrate Class | Rock Substrate Unconsolidated Mineral Substrate |
| Definition | Benthic substrates where percent cover of Rock and Unconsolidated Mineral Substrate exceeds percent cover of both Biogenic and Anthropogenic Substrates, considered separately. When Geologic Substrate is present, but does not constitute the dominant substrate origin, it may be included as a Co-occurring Element. |