1. Introductory . In quitting the Presidential chair of the Edinburgh Geological Society at the end of my term of office, which it has been a pleasure no less than an honour for me to have occupied during the last two years of the bright Nineteenth Century, it has occurred to me that this opportunity might be taken to speak of a subject that has engaged much of my time and attention during the last fifteen years, the first three of which were spent as an officer on the staff of H.M. Geological Survey. The geology of the oil shalefields in the neighbourhood of Edinburgh is a branch of local geology well within the scope of this Society's work, and although the oil industry has existed in this part of Scotland for more than thirty years, no reliable general account has ever been published of the important section of the Lower Carboniferous formation which has so greatly conduced to the well-being of a large district and its people. Such a subject has many features of interest both to the scientific and the economic mind, and I now propose to speak in a popular way of some of the results of my geologisings, in the hope of being able to throw a little new light on the relationships and character of the rocks that have themselves been made, during this generation, to throw so much light over dark places in many a European country. It is not my intention