Individual memoir publications not falling into regular memoir series and issued between 1869 and 1956. The first was 'The Triassic and Permian rocks of the Midland counties of England'. Another, 'The eruptive rocks of Brent Tor' (1878) was an early memoir to contain coloured illustrations of rock thin sections - illustrating the results of the new technique of microscopy petrology. Another example is 'The geology of the Weald' Topley's famous memoir published in 1875.