WW1: Sept 16, 1915

Hi. I notice this forum is about WW2 but I also have an interest in finding out about what happened on Sept. 15, 1916.

My grandmother (Rifleman Edward Smith's mother) lost two cousins (they were brothers) on that date during WW1, but were in different places on that day?.

One, Private Archibald James Viznaugh went MIA age 24(I presume because he is MIA because he's listed as `Remembered' on the Vimy Memorial. Hewas with the Canadian Infantry, Manitoba Regiment, 27th Battalion.

The other brother was Private William Viznaugh, age 18, buried Bapaume Post Military Cemetery. He was with the 1st Canadian Mounted Rifles, Saskatchewan Regiment.

(Their parents moved back and forth between Sask and Manitoba hence any contradiction regards place of birth etc. It was a case of Both/And, not contradictory.)

Can someone in here either tell me anything regards this date/events or at least tell me where I'm likely to find out?

Thanks a lot