Limestone series with its middle-coal-bearing group rise from underneath the Coal-Measures, forming parallel bands curving round the basin. Along the west side of the syncline, the strata dip at high angles to the south-east, are sometimes vertical and even in some cases inverted, while in the centre they become flat and rise at gentle angles towards the east. The Coal Measures and the coal-bearing group of the Carboniferous Limestone series contain numerous valuable coals and ironstones, and there still remains a large field for development. The intrusive igneous rocks forming prominent features in the county are divisible into two main groups, which are separated from each other by a considerable interval of time. The coarse agglomerate filling the old volcano on the top of Arthur's Seat is associated with the eruption of the volcanic rocks of Calciferous Sandstone age near Edinburgh. The fine grained basalt appearing as a plug on the Castle Rock closely resembles the basalt on the top of Arthur's Seat, and is likewise of the same age. The intrusive sheets of Salisbury Crags and Corstorphine Hill composed of olivine-dolerite belong to the same general period. But the quartz-dolerites represented by the Ratho sill are in all probability of late Carboniferous age. _Climate and Agriculture._--In the hill country the average rainfall is 37.4 in., but on the coast only 28.4 in. The average temperature ranges from 38° F. in January to 59°.5 in July, the mean for the year being 47.7. The north-east and easterly winds prevailing in spring are, especially in Edinburgh and its vicinity, remarkable for their cold and blighting character. Excepting in the uplands, snow seldom lies long, but frosts sometimes occur at night as late as the beginning of June, and severe enough to destroy the young shoots of seedling trees in nurseries. But the winter is often astonishingly mild. The common snowdrop (_Galanthus nivalis_) blossoms as early as the 25th of January, the kidney liverleaf (_Hepatica triloba_) by the 31st of January and the rhododendron (_R. nobleanum_) by the 25th of February. On the shores of the Forth along the Almond and the Esk, and on some of the richer flats, grain crops ripen early; 2 m. nearer the hills and 200 ft. higher the harvest is ten days later; and at 600 ft. still another week later. High farming is the rule in the three Lothians. All the area on which wheat can be profitably grown is so occupied; oats, however, is the predominant grain crop, though barley is also raised. Turnips and potatoes are the chief roots, and beans are grown to a limited extent. A large area is occupied by pasture and sown grasses, fallow land having practically disappeared. Near Edinburgh sewage farming has been largely developed. There are 200 acres at Craigentinny between Restalrig and the Forth, besides smaller tracts under similar treatment at Lochend, Dalry and the Grange.