X.— A Vertical Force Magnetic Survey over part of the Dusk Water Fault of North Ayrshire

Abstract

1. Introduction The area comprises the ground flanking the Dusk Water Fault at Auchenmade, near Dalry, North Ayrshire (Fig. 1), is rather less than one square mile in size, and covers a section of the fault just over one mile long. The regional geology is complicated by extensive faulting and folding, but in essentials is represented in Fig. 1. Just east of Dalry, the ground north-west of the Dusk Water Fault is occupied by a south-plunging syncline in the Carboniferous Limestone Series with Millstone Grit (and a small outlier of Coal Measures) near the axis. The Millstone Grit Series consists mainly of basic lavas (about 40 ft. thick at Auchenmade), and crops out in the northern part of the surveyed area. It is underlain by strata of the Upper Limestone and Limestone Coal Groups; the latter also crops out between the Waterside and Auchenmade Faults. South of the Dusk Water—Auchenmade Fault, basic lavas of Calciferous Sandstone age (the visible base of the local succession) form an outcrop in the east of the surveyed area and are succeeded southwards by younger rocks. Thus the Dusk Water—Auchenmade Fault, the most striking structural feature on the map, bisects and distorts the basically simple pattern of a broad south-plunging syncline, bringing rocks at the base of the succession on its southern side into proximity with rocks at the top of the succession on its northern. The only important sequences of known rocks of high magnetic susceptibility in the district are the basic lavas which This 250-word extract was created in the absence of an abstract