Downhill from Albaston, the minor road towards riverside fields passes under Darkey Lane railway bridge, which carries the Tamar Valley Line towards its terminus at Gunnislake. On this unusually clear morning, the sun glistens on dewy pastures and casts long blue tree shadows down frosted banks; beyond the winding loops of the river, Morwell Wood and precipitous rocks remain in shade. Fallen leaves have been washed into drifts along the steep lanes, and hedge banks remain green with pennywort, ferns, ivy and emerging cow parsley, all overhung with sparse, gilded leaves of oak, beech and hazel. Past Oakenhayes House and Slimeford Farm, Calstock’s church tower is silhouetted among trees on the southern horizon, where a two-carriage train crosses another bridge on the sinuous single-track line from Plymouth. The church, graveyard and surrounding land is on a strategic vantage point, set within the Harewood meander, between what was the highest navigable reach and lowest fording place. The Romans established a fort here around AD50, occupied for some 30 years by an estimated 500 soldiers; archaeological surveys also found evidence of an earlier enclosure and pottery dating from the early bronze age (2200-2000BC). The church, constructed in the 14th century, is isolated from the village gathered around quays. These were busy with river traffic until eclipsed by the railway that opened in 1908. Alongside the northern edge of the cemetery, the railway runs in a cutting, carved into the wooded river cliff opposite the historic port of Morwellham. En route to the viaduct, the curving track passes scrubby woodland masking the remains of Okel Tor Mine, and sun-warmed southern slopes once productive with market gardens, nurseries and glasshouses growing tomatoes. We walk down a lane beneath tall beeches to the call of unseen buzzards, over the level crossing and into the village. The tide is on the turn, sparkling scum barely moving; winter’s midday sun dazzles on water flooded over the new wetland intertidal habitat. Beyond this mirror, a few shadowy figures walk along the embankment beside the ebbing river.