Geology for ELR SNK1 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 0256y to 0M 0385y | South Wales Upper Coal Measures Formation - Mudstone, Siltstone, Sandstone, Coal, Ironstone and Ferricrete | ||
| 0M 0385y to 0M 0518y | Pennine Middle Coal Measures Formation and South Wales Middle Coal Measures Formation Ⓤ |