(As usual when it comes to Ireland I am being a bit pathetic with pinning the stories to locations. But I hope the locations still exist).
.. Avowedly malignant ceremonies have been performed at two, if not three, places in East Clare. At Carnelly, near Clare Castle, at an unknown period remote even in 1840, "a black cock, without a white feather," was offered to the Devil on the so-called "Druid's Altar," two fallen pillars near an earthen ring beside the avenue, --to avenge the sacrificer on an enemy, but in this case it brought an equivalent misfortune on the sacrificer himself.
The Duchess de Rovigo, an heiress of the last Stamer of Carnelly, used the story, combined with irrelevant family legends and pseudo-archaeology, in a poem dated 1839, but I obtained it, as given above, from a more reliable source, her mother, in 1875 and 1882, as well as from my brothers and sisters, who heard it in "the forties".
When I was at the dolmen near the house at Maryfort in 1869, an old servant, Mrs. Eliza Ega (nee Armstrong), said to me, -- "Don't play at that bad place where the dhrudes (druids), glory be to God! offered black cocks to the Devil!"
A Folklore Survey of County Clare (Continued)
Thos. J. Westropp
Folklore, Vol. 22, No. 1. (Mar. 31, 1911), pp. 49-60.
A Survey of Monuments of Archaeological and Historical Interest in the Barony of Bunratty Lower, Co. Clare by William Gerrard Ryan
This part of the thesis discusses the various types of monuments of archaeological and historical interest that were noted in the Barony of Bunratty Lower, Co. Clare. Each type of site is examined in turn, under the headings: distribution, features, dating and related sites in Ireland.
In the townland of Kilcarrol in Thomas Keating's land there is a fort by the name of "The Fort of The Black Dog". There was a tree growing in the middle of it, one night a man was going to another house and as he was passing the fort a light appeared before him. The next thing he saw was a black dog. The man turned to run but the dog caught him by the coat and turned him back. The man took up a stick which was beside him and started to beat the dog, but the dog stretched him on the ground. They were fighting for a long time until a man came to them. They both killed the dog and they buried him near the tree and covered him with a pile of stones round, and the stones are to be seen yet and the tree also.
From the Schools Collection of the 1930s, currently being transcribed at Duchas.ie. The black dog isn't overtly described as supernatural (and it seems to be mortal) but its attendant light and habit of lurking about in a fort suggest otherwise to listeners of the story that know these symbols. The Historic Environment Viewer shows quite a collection of interesting things here - the rath, which contains a 'Foot Stone' according to the old 25" map (maybe a foot print of someone in stone?), and also Tobercarroll (a holy well), and a penitential station.