XIII. On a Bed of Fossil Plants, and one of Limestone with Magnesia, in the Calciferous Sandstone Series, at Meikle Busbie, near Ardrossan

Abstract

Meikle Busbie is two-and-a-quarter miles north of South Beach, Ardrossan, and the rocks in its vicinity belong to the calciferous sandstone series, and to the trap which overlies these beds. Immediately to the north of the farm-steading there is an area of porphyrite which extends in a north-west and south-east direction for about two miles, with a breadth of three-quarters of a mile. On the north-east side this trap is sharply cut off by a fault, which brings down the Carboniferous limestone series against it. On the south-west side it lies above the calciferous sandstones at an angle of 40°, and has highly indurated the beds with which it has come in contact. In the trap area several very prominent rocky knolls are dispersed here and there. A small quarry for “road metal” has been opened into one of these trap knolls at a point between the farm-steading and the Dairy and Ardrossan road. Where the plant-bed is seen on the side of the cutting made into the quarry the section is as follows, the strata dipping north-east at 40°:— The trap at the top of the section, which is much weathered at the joints, is roughly columnar, containing veins and cavities filled with crystallized calcite. Some of the calcite is also weathered, and where it is so those curious striations or lines which cross the crystals obliquely on some varieties of calcite, but along which they will not cleave, are weathered into gutters and ridges, as are the cleavage This 250-word extract was created in the absence of an abstract