Black wooden structures on moorside walk

[maccboy]

Bit of an odd one. I've googled it but found nothing.
We were walking near Allgreave across the moors and they're were around 10 black wooden structures on the ground. The nearest things I can describe them to is the thing they practice scrums with for rugby. They were in a line, about 30 yards apart, all facing the same way, and they were numbered. They were about 4 feet high and 4 feet across. My first thought was something to stop any snow drifting but I don't think that is it.
Anyone got any ideas please? I've been to look on Street View but they aren't there. They sort of look like the attached screenshot.

[100SRV]

Points for Grouse shooters?
Maybe rack for the shotguns and shooting post combined.

[cjs racing.]

Stand for grouse shooting.

[maccboy]

Wow! That didn't take long. Look like good answers though. Cheers!