The parish of Malew (from St Lupus, the patron Saint of the district) is bounded on the east by the Santon Burn, on the north by Granite Hill, and South Barrule on the south, by an irregular line from Barrule to Pooil Vash on the west, and by the sea on the east. It covers about 15 square miles.
The southern half of this extensive parish has for its sub-rock a thick series of carboniferous limestones, and is low and undulating, forming part of the southern plain of Castletown. The northern half is high, the hills which form it rising out of the low plain and swelling into the mountains of the southern range.
The chief river is the Silverburn, the western branch of which rises on Barrule, and the eastern branch on the Granite Mountain. The two streams unite above Ballasalla, and flow in a SE direction into the sea at Castletown.
The coast line is low, but rocky and dangerous. It contains two great openings - Derbyhaven, a fine natural harbour, protected by a small breakwater; and Castletown Bay, an inlet between Langness and Scarlett.
The headlands are Dreswick Point and Langness Point, the two extremities of the long, low peninsula of Langness; and Scarlett Point, a conical mass of sub-columnar basalt. The north part of the district, along the slopes of the mountains, is barren and in great part unenclosed; lower, the land is of greater value, and is carefully cultivated.
In the past, employment at Derbyhaven and Castletown was in the fishing trade. At Scarlett and at Ballasalla the population were employed at the extensive lime quames and kilns. Ballasalla used to house large fruit gardens, employing a large number of women and children in the summer months.
Castletown is in this district. The ruins of Rushen Abbey, founded in 1098, and dissolved late in the reign of Elizabeth I, and an ancient bridge over the Silverburn, called the Crossag, or the Monk's Bridge, too narrow for vehicles are also to be found in this area St Mark's, in the northern division of the parish, is a small agricultural village clustered round a chapel of ease. Near it was a huge granite boulder, and an old Danish fort immortalised by Scott in 'Peveril of the Peak'.
In this area:
- Silverdale Glen
- Fort Island
- Derby Fort
- South Barrule
- Rushen Abbey
- St Michaels Chapel