Transactions of the Royal Geological Society of Cornwall, Vol.6 p106 - 107
| Notice of the discovery of a quantity of Pitchblende, at the Providence Mines, near St Ives, Captain Isaac Penberthy, VI: 106-107. |
| Notice of the discovery of a quantity of Pitchblende, at the Providence Mines, near St Ives, Captain Isaac Penberthy, VI: 106-107. |