The atlas's own cited source describes the Currency School as active in the 1840s and 1850s and its currency principle as continuing to shape Bank of England practice into the last quarter of the nineteenth century, but names no single year when the school itself, as an organized analytical camp, stopped being active. The Bank Charter Act of 1844 and the financial crises of 1847, 1857 and 1866 mark policy milestones in its long-running debate with the Banking School, not a stated end date for the Currency School as a school.
What would resolve this A dedicated historiographical treatment tracing when contemporaries stopped writing and organizing as members of the Currency School camp, the same kind of source this atlas already used to date the English Historical School (1890) and the German Historical School (1935), would let a specific end-year be attested here instead of left open.
Openhistory of economic thoughtCurrency School (Wikipedia)