The almond-shaped stone has one consistent color, without visible stratification. It is so fine-grained that minerals are not visible by naked eye. An identical rock is found west of Skeinesset, e.g. at locality 6, a volcanic lava, from former oceanic crust or mantle.
Both along a river and on a beach particles are constantly in motion, either by the river currents or by waves, and from this rounding them. Further along the geo-path you will find an active environment where such processes take place now! These particles are normally cemented into a rock when thick layers of sediments are deposited above, due to increased temperature and pressure.
An untouched layer of conglomerate normally show horizontal stratification, due to horizontally deposition. The conglomerate here has been tilted by a great folding process occuring in the so-called Caledonian orogeny.