Laughton Survey refers to the survey made by Colonel Laughton from 1865 to 1872 and is also called the "Bombay City Survey". The demarcation of lands made under this Survey were taken as prima facie evidence for the purpose of the land revenue administration in Bombay. Under this Survey Boundary marks were fixed on lands lying to the north of Byculla. On the maps under this Survey, Boundary marks were shown by small red circles.
Further Reading: The Gazetteer of Bombay City and Island, 1909.