ice age (n.)
1855, from ice (n.) + age (n.). Perhaps translating German Eiszeit (1837). An earlier term in the same sense was glacial epoch (1841). Local scientific men had noticed from the late 18c. evidence that the Alpine glaciers once had been much larger; in the 1830s stray boulders, moraines, and polished bedrock in northern Europe (formerly interpreted as relics of catastrophic floods) began to be understood as revealing the former presence of a large ice cap there. When Agassiz, a convert to the theory, came to America in 1846 he found similar evidence in New England. The glacial theory and the notion that there had been several worldwide ice ages seems to have been generally accepted by the 1870s.