This column lies in the quarry it was cut from. This is the very same quarry that in 1810 provided the granite pedestal for the Vendôme Column in Paris which was commissioned by Napoleon Bonaparte as a commemoration of victory in the Battle of Austerlitz. Just like Nelson in Trafalgar Square, Napoleon still sits atop the Vendôme for all to see despite being temporarily removed in the 1870's.
Napoleon was of course a native of Corsica, born in Ajaccio and it was Ajaccio that placed the order for this column which was carved in 1836. The plan it is said was to erect a Napoleon's Column in honour of its most famous son. Alas the column proved to heavy to move and instead, other stone from the quarry was used to provide a base for the more modest Casone memorial just above Napoleon's grotto in Ajaccio.
So, it's not just Nelson that has a column nor indeed Santa who has a grotto!