Geological history

The Ochils are hard to miss. Their steep southern slopes rise abruptly from the largely flat valley of the river Forth, dominating the villages that huddle beneath them. The deep glens - Alva Glen among them - are clear in this view.

The story of Alva Glen started 400 million years ago, when molten lava built up in huge thicknesses (more than 2000 metres) to make the mainly basalt rocks that would later form the Ochils. These rocks were then covered by sediments carried by a huge river system. Later periodic flooding caused limestone and coal to be laid down.

The Ochil Hills that we know today were formed when the land to the north of the Ochil Fault rose by hundreds of metres, forming the dramatic southern scarp. The hills were then eroded by ice and water. The V-shaped glens of the Ochils are typical of geologically young valleys cut by water. Alva Glen follows the line of one of the many minor faults in the Ochils.

Silver lining

Did you know that the Ochils contain many deposits of minerals, such as agate, cobalt, and silver? The Erskine family of Alva mined the nearby ‘Silver Glen’ between 1714 and 1770 and great interest was aroused when the extracted ore was found to be one of the richest in silver ever found in Britain. Further excavations were carried out as recently as 1994 but the mines are now thought to be empty.