The fine-grained granite that occurs in dykes is called elvan, which, if easiest to work, is most liable to decay. In Cornwall the elvan of Pentewan was used for the fine church of S. Austell, and as a consequence the weather has gnawed it away, and the greater part has had to be renewed. On the other hand, the splendid elvan of Haute Vienne has supplied the cathedral of Limoges with a fine-grained material that has been carved like lace, and lasts well. The drift that swept over the land would appear to have been from west to east, with a trend to the south, as no granite has been transported, except in the river-beds to the north or west, whereas blocks have been conveyed eastward. This is in accordance with what is shown by the long ridges of clay on the west of Dartmoor, formed of the rubbing down of the slaty rocks that lie north and north-west. These bands all run north and south on the sides of hills, and in draining processes they have to be pierced from east to west. This indicates that at some period during the Glacial Age there was a wash of water from the north-west over Devon, depositing clay and transporting granite. On the sides of the tors are what are locally termed "clitters" or "clatters" (Welsh _clechr_), consisting of a vast quantity of stone strewn in streams from the tors, spreading out fanlike on the slopes. These are the wreckage of the tor when far higher than it is now, _i.e._ of the harder portions that have not been dissolved and swept away. "The tors--Nature's towers--are huge masses of granite on the top of the hills, which are not high enough to be called mountains, piled one upon another in Nature's own fantastic way. There may be a tor, or a group of tors, crowning an eminence, but the effect, either near or afar, is to give the hilltop a grand and imposing look. These large blocks of granite, poised on one another, some appearing as if they must fall, others piled with curious regularity--considering they are Nature's work--are the prominent features in a Dartmoor landscape, and, wild as parts of Dartmoor are, the tors add a notable picturesque effect to the scene. There are very fine tors on the western side of the moor. Those on the east and south are not so fine as those on the north and west. In the centre of the moor there are also fine tors. They are, in fact, very numerous, for nearly every little hill has its granite cap, which is a tor, and every tor has its name. Some of the high hills that are tor-less are called beacons, and were doubtless used as signal beacons in times gone by. As the tors are not grouped or built with any design by Nature to attract the eye of man, they are the more attractive on that account, and one of their consequent peculiarities is that from different points of view they never appear the same. There can be no sameness in a landscape of tors when every tor changes its features according to the point of view