Glaciations were understood in the 18th century,
when extensive observations showed that continental glaciers had covered much
of Europe, North America and Siberia. The position and orientation of the
moraines, striations, and glacial ice flows were detected and detailed maps of
the extension of the ice caps, their direction and the meltwater channel
systems were compiled. This allowed to decipher a story made of multiple
glacial and interglacial periods. [1]
The Vital Needs Theory - page 93