What are these lines on my old plaster (Victorian 1889 Build)

[DJP7]

Good afternoon all,
Had to take a week off work a little while ago (that word beginning with C that everyone has had enough of one way or another).

Rather than sit there and stew I used the time to remove all the horrible plastic wallpaper in our front room (the previous owners had also painted over ). The paper was peeling and there were small mould spots here and there from condensation (I knew nothing about how to care for an older property before moving in).

After a few days of scraping I got the 2 layers of wallpaper off and revealed what I believe to be the original plaster. There is also some skimmed gypsum on the fireplace, around the opening into the second living room and under the windows. I have some questions about under the window but I’ll ask those later.

There is a line on the old plaster around the entire room about a foot from the ceiling. Every metre or so there were rust marks about an inch above it from long, old timey nails that I removed as they were hammered proud of the plaster.

The same coloured markings appear in the corners and around the fire place.

What are these? My guess for the line around the top is some sort of suspended ceiling. No idea about the markings in the corners.

Started reading up about the differences between houses new vs old and find it genuinely interesting. This one is bugging me and haven’t yet come across anything matching.

Any info or help greatly appreciated.

Thanks in advance,

Dan

 

[Koolpc]

Probably had a picture rail at one point.

 

[RandomGrinch]

As above, picture rail and probably built-in cabinets around the fireplace.

A modern interpretation (not my photo! ):