In the course of work on the Midland Coalfields one of the many problems that have occupied attention has been the question of the age of the basalts associated with the Coal Measures. Extrusive basic igneous rocks that are known to be of Lower Carboniferous age occur at Little Wenlock in Shropshire, in the Bristol district, in North Staffordshire, in Derbyshire, and in Cumberland. Rocks of similar type are present in the Upper Carboniferous of the Midlands, but hitherto no definite evidence of their age has been produced. The distribution of these rocks is shown on the accompanying map (Pl. I). The Butterton and Swynnerton dyke in North Staffordshire and the Grinshill and Acton Reynald dyke in North Shropshire both traverse the Keuper Marl and are therefore definitely post-Triassic. Kinlet.—The Kinlet basalt lies approximately between the Sweet Coal (Yorkian) and Sulphur Coal (Staffordian) Groups of the Wyre Forest Coalfield; that is, in the position of the unconformity or ‘Symon Fault’ in the Coalbrookdale Coalfield. In an old quarry about 300 yards S. 20° W. of Mass House Farm, near Kinlet, the following section is exposed:— Feet. Inches Sandstone, yellowish-buff, flaggy. The lower layers are dark btrn in colour and consist of sand grains in a matrix of decomposed basaltic material with pebbles of basalt and portions of amygdales. 2 0 Coarse grit of small quartz pebbles up