Dykes have been described as travelling, running or linear earthworks. All these terms express their essential character, that of a bank, usually of earth but occasionally of loose stone, extending for a considerable distance across country. The existence of a bank presupposes an adjacent ditch from which its material was derived, and the descriptive term Ditch is as common as Dyke in the nomenclature of linear earthworks. Both terms have indeed a common origin.

Most prehistorians are aware of the existence of a group of rock carvings depicting oxen, ploughs,etc., on the slopes around Monte Bego in the Italian Maritime Alps. As long ago as 1650 they were mentioned by the historian Gioffredo in his History of the Maritime Alps. Since then the only people of archaeological importance who appear to have paid visits to a certain few of the carvings were M. Rivière, in 1877, Professor Celesia in 1885, and Sr. Barocelli in recent years. It was, however, only when the late Clarence Bicknell, a keen botanist who lived at Bordighera, visited the Monte Bego district in search of alpine flowers and became interested in the carvings that a systematic study of them was commenced. For the best part of twenty years, from 1897 onwards, Bicknell worked on both sides of Monte Bego examining and taking rubbings of all the figures he could find. In all, something like 15,000 figures were thus studied, and for the purpose Bicknell built himself a house in the Val Casterino. This is a high, upland valley leading off the Miniera valley which is itself a side valley to the Upper Roya and runs up from San Dalmazzo di Tenda on the Franco-Italian frontier. The Casa Fontanalba, as he named the house, is beautifully situated just at the mouth of the Val Fontanalba, a narrow, steep valley running up from the Val Casterino to Monte Bego itself. The existence of the Casa as a base of operations made a careful study of the carvings possible, but even so they cannot be reached without a two to three hours walk and climb from the house-and it is uphill going all the way !

The area considered in this study is roughly the drainage of the Wharfe and its tributary the Skirfare, above Burnsall, a typical ‘Yorkshire Dale’. The valley is excavated through the Yoredale series of alternating limestones, shales, and sandstones, into the Great Scar Limestone, the lowest member of the Carboniferous series. This lower limestone forms very imposing and massive scars along the valley sides, above which the fells rise in a series of steps and scars corresponding with the limestone and sandstone outcrops. The valley bottom is occupied by a series of glacial lake flats and moraines which have played a very important part in the settlement of the valley, the lake flats being swamp until recently drained, and still liable to flood through a great part of winter, the moraines providing dry crossing places and village sites throughout the upper dale. The dale under discussion is about 20 miles long, and from ¼ to ½ mile wide between the lower scars of limestone. The valley floor rises from 500 ft. above sea-level at Burnsall to 1250 ft. at the head of the valley near Oughtershaw,while the top of the first scar varies from 800 ft. to about 1600 ft., being a platform of good pasture about a third of a mile wide, on each side of the valley.

So Caistor-by-Norwich is to be excavated. It has long been known that in the 30-acre field adjoining the little church of St. Edmund a ghost of the Roman town shows dimly from time to time as a net-work of lines in the sun-dried corn. Last year on the 20th of July, during the midsummer heat-wave, a Royal Air Force aeroplane, flying at a height of 2400 feet over the ripening barley, took a series of photographs which were first published (as a single plate) in the Times of 4th March 1929. These photographs show, within the circuit of the existing Roman town-walls, the main street-plan of Venta Icenorum. With them appeared an appeal for funds for the purpose of excavation.

The mountain known as Mongó is an isolated mass of limestone, rising to a height of over 2500 feet above the level plains which border the sea in the neighbourhood of Denia in the ancient territory of the Contestani and the modern province of Alicante (pl. I). Standing free, as it does, from the main mass of mountains, it is the most conspicuous landmark on the promontory which stretches eastwards towards the Balearic Islands. The views from its summit cover a wonderful expanse of country; south and westwards to the mountains, northwest across miles of orange groves to the coast leading to Valencia and beyond (pl. 6), while eastwards the Isle of Ibiza is clearly visible 70 miles away.

The arid plateau of the Judaean wilderness drops on the east to the trough of the Dead Sea in a long range of sheer cliffs, which are pierced about 32 miles south of the mouth of the Jordan by the ravine of the Wad-el-Hâfâf. On its northern flank a huge mass of their red limestone has split away to form an isolated flat-topped crag standing 1700 feet above the Dead Sea about a mile and a half from its western shore.