Geology for ELR BAL 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 0188y to 0M 0275y | Clay, Silt and Sand | Alluvium | Lias Group - Mudstone, Siltstone, Limestone and Sandstone |
| 0M 0275y to 0M 0385y | Sand and Gravel | Glacial Sand and Gravel | Lias Group - Mudstone, Siltstone, Limestone and Sandstone |
| 0M 0385y to 0M 0715y | Sand and Gravel | Glacial Sand and Gravel | Triassic Rocks Ⓤ - Sandstone and Conglomerate, Interbedded |
| 0M 0715y to 1M 0055y | Clay, Silt and Sand | Alluvium | Triassic Rocks Ⓤ - Sandstone and Conglomerate, Interbedded |
| 1M 0055y to 1M 0495y | Clay, Silt and Sand | Alluvium | Dinantian Rocks Ⓤ - Limestone with Subordinate Sandstone and Argillaceous Rocks |
| 1M 0495y to 2M 0165y | Clay, Silt and Sand | Alluvium | Millstone Grit Group - Mudstone, Siltstone and Sandstone |
| 2M 0165y to 2M 0825y | Clay, Silt and Sand | Alluvium | Pennine Lower Coal Measures Formation and South Wales Lower Coal Measures Formation Ⓤ |
| 2M 0825y to 2M 1485y | Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation Ⓤ | ||
| 2M 1485y to 3M 0165y | Clay, Silt and Sand | Alluvium | Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation Ⓤ |
| 3M 0165y to 5M 0935y | Clay, Silt and Sand | Alluvium | South Wales Upper Coal Measures Formation - Mudstone, Siltstone, Sandstone, Coal, Ironstone and Ferricrete |
| 5M 0935y to 5M 1375y | South Wales Upper Coal Measures Formation - Mudstone, Siltstone, Sandstone, Coal, Ironstone and Ferricrete | ||
| 5M 1375y to 6M 0935y | Clay, Silt and Sand | Alluvium | South Wales Upper Coal Measures Formation - Mudstone, Siltstone, Sandstone, Coal, Ironstone and Ferricrete |
| 6M 0935y to 7M 0385y | Clay, Silt and Sand | Alluvium | Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation Ⓤ |
| 7M 0385y to 7M 0495y | Diamicton | Till | Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation Ⓤ |
| 7M 0495y to 7M 0715y | Clay, Silt and Sand | Alluvium | Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation Ⓤ |
| 7M 0715y to 8M 0055y | Diamicton | Till | Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation Ⓤ |
| 8M 0055y to 8M 0275y | Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation Ⓤ | ||
| 8M 0275y to 9M 0317y | Diamicton | Till | Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation Ⓤ |