On the Fossiliferous Rocks of Forfarshire and their Contents

As stated in a former paper, the lower members of the Forfarshire Old Red Sandstone consist of gritty beds and pebbly conglomerates having a highly indurated matrix, passing upwards into conglomerates formed of the same kind of pebbles as in the lower, but imbedded in a softer, matrix, it being of a consistence similar to that of the intercalated and overlying sandstones. Occupying a position intermediate between the more indurated lower and the softer upper strata are found the flaggy beds which yield the well-known Arbroath paving-stones. These flaggy beds, although rather intercalated than interstratified in the conglomerates, are of great extent and very considerable thickness, especially along and on both sides of the anticlinal line of Forfarshire (its position is pointed out in the paper above referred to); they consist of alternating layers of shales and freestones. The freestones are sometimes thick and solid-bedded, affording an excellent building-stone, sometimes raised in layers thin enough to be generally used as roofing-slates, although of very inferior quality, and sometimes of sufficient thickness to form good, but rather soft, paving-stones.