ological ▁and ▁arch ae ological ▁subjects , ▁including ▁the ▁controvers ial ▁identification ▁of ▁“ e ol ith s ,” ▁or ▁possible ▁primitive ▁stone ▁tools ▁d ating ▁well ▁back ▁into ▁the ▁Ple ist oc ene . ▁ ▁In ▁ 1 9 0 7 , ▁Eng err and ▁moved ▁to ▁Mexico , ▁where ▁he ▁continued ▁his ▁work ▁in ▁both ▁arch ae ology ▁and ▁ge ology ▁and ▁became ▁a ▁Mexican ▁citiz en ▁in ▁ 1 9 0 8 . ▁He ▁was ▁a ▁professor ▁of ▁pre history ▁at ▁the ▁National ▁Museum ▁of ▁Anth rop ology ▁and ▁a ▁successor ▁to ▁Franz ▁Bo as ▁as ▁director ▁the ▁Esc uela ▁Internacional ▁de ▁Ar que ología ▁e ▁Historia . ▁Among ▁many ▁contributions , ▁he ▁played ▁a ▁key ▁role ▁in ▁developing ▁a ▁pre histor ic ▁strat ig raph ic ▁chron ology ▁for ▁the ▁Valley ▁of ▁Mexico ▁and ▁in ▁investig ating ▁rock ▁art ▁in ▁north western ▁B aja ▁California . ▁ ▁However , ▁the ▁political ▁climate ▁during ▁the ▁Mexican ▁Revolution ▁was ▁unf avor able , ▁and ▁in ▁ 1 9 1 7 ▁Eng err and ▁again ▁em igr ated ▁to ▁the ▁United ▁States . ▁After ▁teaching ▁briefly ▁in ▁Mississippi , ▁he ▁served ▁as ▁a ▁member ▁of ▁the ▁University ▁of ▁Texas ’ s ▁anth rop ology ▁department ▁from ▁ 1 9 2 0 ▁until ▁ 1 9 6 1 , ▁producing ▁an ▁eth n ographic ▁study ▁of ▁the ▁German ▁imm igr ant ▁community ▁of ▁W ends ▁in ▁Texas . ▁ ▁References ▁▁ ▁Category : F rench ▁ge olog ists ▁Category : M ex ican