Geology for ELR YAT is based on British Geological Survey (BGS) low-resolution data sampled at 100 metre intervals along the ELR. The geology presented should not be treated as accurate or complete. Data marked with Ⓤ is classed as undifferentiated by the BGS.
| Mileage | Material | Deposit | Bedrock |
|---|---|---|---|
| 119M 1580y to 120M 1485y | South Wales Upper Coal Measures Formation - Mudstone, Siltstone, Sandstone, Coal, Ironstone and Ferricrete | ||
| 120M 1485y to 121M 0165y | Triassic Rocks Ⓤ - Mudstone, Siltstone and Sandstone | ||
| 121M 0165y to 121M 0613y | South Wales Upper Coal Measures Formation - Mudstone, Siltstone, Sandstone, Coal, Ironstone and Ferricrete |