174 THE ESSEX NATURALIST Referring to Salter's catalogue we found mention of other isolated conglomerate blocks at Cripsey Brook (505067), Leaden Roding (595135), and Mashbury Hall (652118). Plotted as a straight line on the one-inch map, the Cripsey stone led on to Fyfield ; the Leaden Roding stone was in line with Felsted ; and the Mashbury stone was roughly in line with another men- tioned by Salter, at White Notley. We investigated these tracks in turn. The Cripsey stone was immediately rejected, for we found that the bed of the Cripsey Brook near Moreton was a prolific source of this stone, which is a favourite material for local rockeries. The Leaden Roding track was similarly abandoned, for the stone which in Salter's day stood outside the Inn has long since disappeared, and it was apparently placed there originally as a mounting block. This left us with the Mashbury track. We adopted as a first principle a critical approach to all evidence met with, accepting no site or station without personal examination and cross-ques- tioning of witnesses. Over the six months of this preliminary enquiry we have sifted the testimony of more than two hundred witnesses. We have adduced ample evidence of a track marked out by a series of sighting stones all of conglomerate rock, an astonishing number of which still exist in their original situations. Other evidence, such as green roads and moated mounds, was noted, but at no time have we rested our deductions on such alone. There is strong presumptive evidence of this track stretch- ing for eighty miles in a series of straight segments, making a great arc from Hertfordshire, through Essex, Suffolk, and Nor- folk to the Wash. We have convincingly plotted more than fifty miles of it, and have followed with confident certainty more than twenty miles. The pattern of the conglomerate track is so con- firmed that we can anticipate where a stone will be found ; some in our list have been discovered in this way. We are convinced of the deliberate placing of these stones by human agency by our experience that in spite of systematic search we have found no similar stones anywhere else except such as can be traced to natural sources such as the beds of rivers and natural outcrops, and those which have been placed in position in living memory. The following is a detailed list of the markstones and other phenomena found during this summer. The list is by no means complete, for other items are constantly being dis- covered. National Grid reference numbers are given for purposes of identification, and total distances are given in miles and furlongs from the River Lea.