 The town rests on Forest Marble which dates back to the Middle Jurassic, and has been used for local building. The area surrounding the town is Cornbrash, Oxford Clay and Greensand. Frome is unevenly built on high ground above the River Frome, which is crossed by the 16th century town bridge in the town centre. The town centre is approximately 65 metres (213 ft) above sea-level, whilst the outer parts of the town are between 90 metres (295 ft) and 135 metres (443 ft) above sea-level.
