Geology for ELR TAD 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 |
|---|---|---|---|
| 0M -066y to 0M 0055y | Arenig Rocks Ⓤ - Mudstone, Siltstone and Sandstone | ||
| 0M 0055y to 0M 1045y | Clay, Silt and Sand | Alluvium | Arenig Rocks Ⓤ - Mudstone, Siltstone and Sandstone |
| 0M 1045y to 2M 0383y | Arenig Rocks Ⓤ - Mudstone, Siltstone and Sandstone |