There are many aspects of geology demonstrated in the area around Hillswick. The Red sandstones and Volcanic lavas of Eshaness, which have produced spectacular cliff scenery are unmissable and the geology is explained on the information board.

The Ness at Hillswick itself has much to offer with a variety of metamorphic rocks mostly running East to West which you will cross as you walk southwards. A view from the west cliffs on the Ness displays the igneous rock of The Drongs which so far have dramatically withstood the ravages of the sea, is the highlight of the walk.

Even before arriving at Hillswick have a brief pause at Mavis Grind to look at the geological display  which shows  twenty of the rocks which make up Northmavine.
With a car North Roe and Fetharland are both within reach, and they have varied geology to see whilst nearer at hand the two major faults are visible. The first is the Walls Boundary Fault, best seen at Ollaberry beyond the churchyard on the cliff path and is a continuation of the Great Glen fault where the rocks have been laterally displaced some 100km; at this location granite gneiss lies against Hornblende Schist. The other fault at Breiwick is the Melby Fault which separates the Granite of Ronas Hill from the Sandstone rocks of the Eshaness peninsular.

For more information visit  the Tangwick Museum to see the geological maps of the area. The main museum at Lerwick does exhibit many of the rocks and minerals as well as photographs of the Hillswick and Northmavine area and is well worth a visit.