A horizontal cross-section at a scale of 300 feet to the inch and vertical section 100 feet to the inch dated December 1839 made by Thomas Sopwith (1803–1879) of Newcastle spans the Carboniferous Limestone from Cross Gill, Cumberland to Hownes Gill, Co. Durham, and measures 42 feet long (~13 m) by 2 feet 5 inches deep (nearly 1 m). The section is now owned by Graham Carlisle, who will be present during the paper to display it and answer questions about its provenance.

Sopwith must have walked the ‘28 miles 12 chains 60 links’ as he knew the whole district when young walking hills and dales learning his geology by observation. Sopwith decided in 1824 to train as a lead-mine surveyor at his own expense and became apprenticed to J. & T. Dickinson (or Dickenson) of the north of England lead mines. There he undoubtedly devoured Westgarth Forster's (1809, 1821) classic of the geology from Newcastle to Cross Fell to which his mentors were subscribers. As Rudwick pointed out in 1976, Forster was the first to provide stratigraphic columns; Sopwith produced his own first book with sections in 1829 based on his apprenticeship years and a further one in 1833. From his diary we know that Sopwith was fully aware of Werner's ideas (1809 translation) but it was the influence of Buckland and Smith that swayed his emphasis. On the section there are pencil notes regarding colours to be used; colour coding was one of Sopwith's fortés, this example predating work at the W.B. Lead Mines, where he was chief agent from 1845. The purpose of the section is not yet certain but he was working that year or the previous one on a model of part of Alston Moor and Nentsbury lead mines (his model XVI) and he exhibited on Alston Moor strata at the 1838 British Association for the Advancement of Science (BAAS), and on November 6th 1839 Sopwith lectured to Durham University students about plans, sections, geological drawings, and models, and even Adam Sedgwick viewed it. Since the 1820s Sopwith had honed his skills in isometric drawing in this area and made sections and later the large one-off model to show structure; by the late 1830s he had begun to think about making his smaller models. This is Sopwith’s two-dimensional magnum opus, the result of his early fieldwork on his testing ground in the northern Pennines. Sopwith's field skills were recognised in late 20th century by K. C. Dunham and later geologists working in the same area, and, based on the associated maps, one of these men may have owned the Sopwith section in the mid-1970s.