Complex sentence: By June the 3rd Division was finally approaching Salamaua, with the 17th Brigade advancing from the south-south-west, supported by two 3.7 inch howitzers from the 1st Mountain Battery as well as one US field battery.
Split into simpler sentences: By June the 3rd Division was finally approaching Salamaua, with the 17th Brigade advancing from the south-south-west. The Brigade was supported by two 3.7 inch howitzers from the 1st Mountain Battery as well as one US field battery.