Complex sentence: The South Africans began to dig in around the fringe of the wood in groups, forming strong--points supported by machine-guns, in a salient and in touch with the 26th Brigade only along the south-western edge of the wood next to Longueval.
Split into simpler sentences: The South Africans began to dig in around the fringe of the wood in groups, forming strong--points supported by machine-guns. The brigade was in a salient and only in touch with the 26th Brigade along the south-western edge of the wood next to Longueval.