Complex sentence: Even on the far left, opposite Flagstaff and Central bastions, there was severe hand-to-hand fighting, and throughout the day the bombardment mowed down the Russian masses along the whole line.
Split into simpler sentences: Even on the far left, at the opposite Flagstaff and Central bastions, there was severe hand-to-hand fighting. And throughout the day the bombardment mowed down the Russian masses along the whole line.