You can view a better version here
https://maps.nls.uk/geo/explore/#zoom=17.3&lat=52.75295&lon=-6.71879&layers=6&b=ESRIWorld&o=100&marker=52.752934,-6.717127
(It is one of the Six Inch maps, but same idea.)
The direction of the 'teardrop' marks indicates the bottom of the slope. There are only arrows pointing inwards, meaning it is likely a pit, cutting or similar.
(surface pits are quaries in OSM.)
Archaeological sites (mainly ringforts) which you refer to ausually have an embankment, which is indicated with two sets of 'teardrops' pointing in opposite directions, or on other variants it is marked as dense set of straight lines pointing outward (connected by ring or not).
You can find style sheets for these maps here
https://maps.nls.uk/view/128076891

Note, not all embankments (mainly unclosed straight-ish segments) indicate an archaeological site. Some are (modern) artificial or natural slopes or bumps/erosion. They were recorded because they are/were sufficiently visible in the landscape or were possible fortifications but turned out not to be. Most of these do not have an entry on HEV.

(In case you are not aware yet, we can use the historic maps on National Library of Scotland for OpenStreetMap. As opposed to the maps present on Historic Environment Viewer, which we can't use. We can only use those for reference when surveying.)

NLS:
https://maps.nls.uk/os/6inch-ireland/index.html

HEV:
https://heritagedata.maps.arcgis.com/apps/webappviewer/index.html?id=0c9eb9575b544081b0d296436d8f60f8

How to use the HEV
https://www.youtube.com/watch?v=MDILb9r0VX0

If it is not on HEV, and you think it is an archaeological site, you can mark it as
maybe:historic=archaeological_site
note=Not on HEV.
You're welcome to report any possible sites using the NMS monument report form.

Reporting a possible monument
https://www.youtube.com/watch?v=SAXIJsxD1wU

Happy mapping :-)