Such a sighting line (or ley) would be useless unless some further marking points on the lower ground between were made. Therefore secondary sighting points were made, easily to be seen by the ordinary user standing at the preceding sighting point, all being planned on one straight line. These secondary, and artificial, sighting points still remain in many cases, either as originally made, or modified to other uses, and a large number are marked on maps, and are the basis of my discovery. They were constructed either of earth, water or stone, trees being also planted on the line. Sacred wells were sometimes terminals in the line, and sometimes included as secondary points. Between the sighting points the trackway ran straight, except in cases of physical impossibility, but did not of necessity go as far as the primary hill tops. Earth sighting points were chiefly on higher ground, and now bear the name of tump, tumulus, mound, twt, castle, bury, cairn, garn, tomen, low, barrow, knoll, knap, moat and camp. Another form of earth sighting point was in the form of a notch or cutting in a bank or mountain ridge which had to be crossed by the sighting line. Water sighting points seem to have evolved from the excavations made for the tumps or moats. Almost all are on low ground, to form a point or ring of reflection from higher ground, and are now known as moats and ponds. Stone sighting or marking points were natural (not dressed) blocks. Sighting lines were (in earliest examples) up to 50 or 60 miles in length, later on rather shorter, down to a few miles. Sighting points were used for commerce and for assemblies of the people. [Illustration: PLATE III. MOUND AND MOAT. 1. Houghton Mound. 2. Lemore Moat.] [Illustration: PLATE IV. THREE-POINT PROOFS. 1. Sighting Pond, Hereford Cathedral, Pen-y-Beacon. 2. Ford at Llanvihangel Mill, Road, Tre-Fedw Mound. (See Plate II.)] When troublesome times came and stronger defences wanted, the groups of two or three sighting tumps which came near together (especially on the top of a hill) often had defensive earthworks added to make a fortified enclosed camp. These trackways of successive ages grew so thick on the ground as to vie in number with present day roads and by-ways. All forms of sighting points became objects of interest, superstition, and genuine veneration, and as such were utilized on the introduction of Christianity. Practically all ancient churches are on the site of these sighting points (tumps or stones), usually at a cross of tracks, and there is evidence that in some cases the churchyard cross is on the exact spot of the ancient sighting or marking stone. In time, homesteads clustered round the sighting points, especially the ponds. The moats and tumps were often adopted in after ages as sites for the defensive houses or castles of wealthy owners. Hundreds of place names give support to these propositions.