Attention has been frequently drawn to curious round pits so often found on the stones of dolmens and usually known as cup-markings.  They vary in diameter from about two to four inches, and are occasionally connected by a series of narrow grooves in the stone.  They vary considerably in number, sometimes there are few, sometimes many.  They occur nearly always on the upper surface of the cover-slab, very rarely on its under surface or on the side-walls.

Some have attempted to show that these pits are purely natural and not artificial.  It has been suggested, for instance, that they are simply the casts of a species of fossil sea-urchin which has weathered out from the surface of the stone.  This explanation may be true in some cases, but it will not serve in all, for the ‘cups’ are sometimes arranged in such regular order that their artificial origin is palpable.  These markings are found on dolmens and corridor-tombs in Palestine, North Africa, Corsica, France, Germany, Scandinavia, and Great Britain.  In Wales there is a fine example of a dolmen with pits at Clynnog Fawr, while in Cornwall we may instance the monument called “The Three Brothers of Grugith” near Meneage.

There is no clue to the purpose of these pits.  Some have thought that they were made to hold the blood of sacrifice which was poured over the slab, and from some such idea may have arisen some of the legends of human victims which still cling round the dolmens.  Others have opposed to this the fact that the pits sometimes occur on vertical walls or under the cover-slabs, and have preferred to see in them some totemistic signification or some expression of star-worship.  It is possible that we have to deal with a complex and not a simple phenomenon, and that the pits were not all made to serve a single purpose.  Those which cover some of the finest stones at Mnaidra and Hagiar Kim are certainly meant to be ornamental, though there may be in them a reminiscence of some religious tradition.  In any case, it is worth while to remember that cup-markings also occur on natural rocks and boulders in Switzerland, Scandinavia, Great Britain (where there is a good example near Ilkley in Yorkshire), near Como in Italy, and in Germany, Russia, and India.

Of the builders of the megalithic monuments themselves we cannot expect to know very much, especially while their origin remains veiled in obscurity.  Yet there are a few facts which stand out clearly.  We even know something about their appearance, for the skulls found in the megalithic tombs have in many cases been subjected to careful examination and measurement.  Into the detail of these measurements we cannot enter here; suffice it to say that the most important of them are the maximum length of the skull from front to back and its maximum breadth, both measures, of course, being taken in a straight line with a pair of callipers, and not round the contour of the skull.  If we now divide the maximum breadth by the maximum