Geology
During the construction of the railway in 1892, the geologist T. V. Holmes discovered a 5 metre layer of boulder clay underlying the gravel and sand in a section just north of St Andrews Park. This is now the Hornchurch Cutting Site of Special Scientific Interest, which exhibits the southernmost limit of the Anglian ice sheet 450,000 years ago, the furthest south that any ice sheet reached.
Read more about this topic: Romford To Upminster Line