The Society has had its attention of late so much directed to the subject of coal, that some apology, perhaps, is necessary for bringing this substance again under notice. I may premise, however, that in doing so, it is not my intention to revive the disputed question as to Boghead gas-coal, nor to take up the time of the Society with what may be considered as unprofitable discussion. I purpose to bring forward a few facts relative to a coal, concerning which there is no dispute, and which presents some vegetable organisms and products calculated, in my opinion, to throw light on the history of carboniferous deposits. Much of the recent difference of opinion on the question of coal has arisen from the mode in which some histologists have chosen to define it. I trust that the result of all our discussions will be to lead to a fuller examination of coal in all its forms,—to a comparison of specimens, both mineralogically and microscopically, from different localities,—and, finally, to an extended report on the subject in which geologists, chemists, and histologists will combine.