+---+---+-------------------------------------------+----------------------------------+ | | | Europe. | North America. | +---+---+-------------------------------------------+----------------------------------+ | Q | \ Historic, up to the present time. | Similar to the European | | u | \ Prehistoric, comprising deposits of | development, but with scantier | | a | \ the Iron, Bronze, and later | traces of the presence of man. | | t | \ Stone Ages. | | | e | \ Neolithic--alluvium, peat, lake- | | | r | Recent, \ dwellings, loess, &c. | | | n | Post- | Palaeolithic--river-gravels, cave- | | | a | glacial | deposits, &c. | | | r | or | | | | y | Human. | | | | | | | | | o | | | | | r +---------+-------------------------------------+----------------------------------+ | | Pleist- | Older Loess and valley-gravels; | As in Europe, it is hardly | | P | ocene | cave-deposits. | possible to assign a definite | | o | or | Strand-lines or raised beaches; | chronological place to each of | | s | Glacial.| youngest moraines. | the various deposits of this | | t | | Upper Boulder-clays; eskers; marine | period, terrestrial and marine.| | | | | sands and clays. | They generally resemble the | | T | | Interglacial deposits. | European series. The | | e | | Lower boulder-clay or Till, with | characteristic marine, | | r | | striated rock-surfaces below. | fluviatile and lacustrine | | t | | | terraces, which overlie the | | i | / | older drifts, have been | | a | / | classed as the Champlain Group.| | r | / | | | y | / | | | . | / | | +---+---+-------------------------------------------+----------------------------------+