Ironstone mining in Cleveland and North Yorkshire occurred on a sizeable scale from the 1830s to the 1960s in present-day eastern parts of North Yorkshire but was recorded as far back as Roman times mostly on a small scale and intended for local use. Around the year 1850, large seams of ironstone were discovered in the Cleveland Hills, later also in and around Rosedale and Eskdale. Mining of these seams accelerated an industry around the River Tees's south eastern banks and around the River Tyne, where many new ironworks were built. Settlements around the Tees and Tyne, especially the Cleveland town of Middlesbrough developed as iron- and steel-processing centres. They received large amounts of ironstone, first by ship and later by railway. The industry experienced a meteoric rise, in the space of twenty years, and ironstone from the Cleveland part of Yorkshire was supplying 38% of the steel and iron requirements of Britain.