Sub-Boreal
Concise Oxford English Dictionary © 2008 Oxford University Press:
Sub-Boreal /ˈbɔːrɪəl/
▶adjective Geology relating to or denoting the fourth climatic stage of the postglacial period in northern Europe (about 5,000 to 2,800 years ago).
'Sub-Boreal' also found in these Oxford entries:

