Geology for ELR GTW1 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 |
|---|---|---|---|
| 30M 0012y to 30M 0385y | White Chalk Subgroup - Chalk | ||
| 30M 0385y to 30M 0935y | Lambeth Group - Clay, Silt, Sand and Gravel | ||
| 30M 0935y to 35M 1108y | Thames Group - Clay, Silt, Sand and Gravel |