th ▁Army ▁near ▁Am iens , ▁to ▁attack ▁west wards ▁to ▁the ▁coast ▁and ▁then ▁en velop ▁the ▁French ▁northern ▁fl ank ▁south ▁of ▁the ▁Som me . ▁The ▁off ensive ▁by ▁the ▁French ▁Second ▁Army , ▁forced ▁Fal ken h ay n ▁to ▁di vert ▁the ▁XX I ▁and ▁I ▁Bav arian ▁Corps ▁as ▁soon ▁as ▁they ▁arrived , ▁to ▁extend ▁the ▁front ▁north wards ▁from ▁Cha ul nes ▁to ▁P ér onne ▁on ▁ 2 4 ▁September ▁and ▁drive ▁the ▁French ▁back ▁over ▁the ▁Som me . ▁On ▁ 2 6 ▁September , ▁the ▁French ▁Second ▁Army ▁d ug ▁in ▁on ▁a ▁line ▁from ▁L assign y ▁to ▁Ro ye ▁and ▁B ray - sur - S om me ; ▁German ▁caval ry ▁moved ▁north ▁to ▁enable ▁the ▁II ▁Bav arian ▁Corps ▁to ▁occup y ▁the ▁ground ▁north ▁of ▁the ▁Som me . ▁On ▁ 2 7 ▁September , ▁the ▁German ▁II ▁Caval ry ▁Corps ▁drove ▁back ▁the ▁ 6 1 st ▁and ▁ 6 2 nd ▁Reserve ▁divisions ▁( General ▁Joseph ▁Bru g ère , ▁who ▁had ▁replaced ▁General ▁Albert ▁d ' A made ), ▁to ▁clear ▁the ▁front ▁for ▁the ▁XIV ▁Reserve ▁Corps ▁and ▁link ▁with ▁the ▁right ▁fl ank ▁of ▁the ▁II ▁Bav arian ▁Corps . ▁The ▁French ▁ ▁began ▁to ▁assemble ▁at ▁Ar ras ▁and ▁Ma ud ' hu y ▁found ▁that ▁instead ▁of ▁making ▁another ▁attempt ▁to ▁get ▁round ▁the ▁German ▁fl ank , ▁the ▁sub div ision ▁was ▁men ac ed ▁by ▁a ▁German ▁off