The Grimstone Down Earthworks
English Heritage have made available a 1952 volume entitled “Stratton, An Inventory of the Historical Monuments in Dorset, Volume 1: West” [pages 226 – 229] which provides details of earthworks adjacent to Jackman’s Cross.

50 yards to the north-east of the cross is a bowl barrow 52 feet in diameter and 5½ feet high. The photograph below was taken in May 2014.
There is another in Coronation Plantation, some 350 yards to the north-east. It is 42 feet in diameter and 4½ ft. high. It has been disturbed in the middle. A third bowl barrow can be found ¼ mile north-west of the cross. It is 38 feet in diameter and 3 feet high.

On Grimstone Down, a little to the south-west of Jackman’s Cross are traces of Celtic fields covering more than 100 acres. The image below shows part of the area photographed in May 2014. Towards the middle of the area the fields become more clearly defined and between the field-banks several hollowed tracks converge on a series of smaller enclosures; these, though they show no traces of dwellings, no doubt represent the position of the main settlement. The smaller enclosures include a small rhomboidal one with an entrance on the west and a possible entrance on the east and a larger enclosure adjoining the smaller and having an entrance on the north; the bank is turned inwards on either side of the entrance and there are traces of a hollowed track through the enclosure. The southern end of the group has been much destroyed but traces survive of a third small enclosure and about 100 yards to the south of two small enclosures.
A sketch plan in the 1952 volume illustrates the Grimstone Down Settlement. Jackman’s Cross is off the plan a little to the north-east.
There are eight bowl barrows on Grimstone Down. (1) 540 yards south-south-west of Jackman’s Cross and 220 yards west of Grimstone Down Plantation. It is 50 feet in diameter and 5 feet in height; it has been disturbed in the middle. (2) 20 yards east of (1) It is 36 feet in diameter and was in 1952 1½ feet high. It has been much disturbed in the middle. (3) 155 yards east by north of (1), it is 27 feet in diameter and 2½ feet high. It has been disturbed. (4) 240 yards west by south of (1). It is 45 feet in diameter and 5 feet high. (5) 390 yards south-west of (1). It is 35 feet in diameter and 2½ feet high. (6) 68 yards west-south-west of (5). It is 22 feet in diameter and 2½ feet high. (7) 150 yards east-north-east of (5). It is 18 feet in diameter and 3 feet high. (8) In the southern of the two Grimstone Clumps. It is about 52 feet in diameter and 5 feet high. This barrow, photographed in May 2014, is shown below.
In an area about 320 yards north-north-east of (1) there are a number of slight mounds possibly the remains of barrows now too indefinite for measurement.To the north of Lawyer's Plantation, north-east of Grimstone Down, is a dyke and beyond it to the east are further remains of a Celtic field-system. This system extended some distance to the south. The dyke extends across the ridge and the ditch at its best preserved point is 13 feet wide and 1¾ feet deep. There are remains of a bank on the south-west about 11 feet wide and 1 foot high and traces also of a bank to the north-east which, however, appears to be no part of the original work.