Although many theories have been suggested to account for the formation of coal-beds, all of which agree in the vegatable origin of the coal itself, none have yet apperared which meet many of the difficulties which surround the subject of their origin, and probably they have been deposited under so many varying conditions that no one supposition would account for the difference in the constituents of the mineral, or for the mode of its formation in different localities. From the Stigmaria found in the underclay, in the great majority of cases, it seems fair to assume that the vegetation from which the coal above it was formed, grew where the coal is found, and there are other reasons for coming to the some conclusion in these cases, but in some places, where the underclay is wanting, this may be doubtful.

The fashionable Belgian watering place, Spa, is situated 1000 feet above the sea, in the centre of a circle of hills called the High Moors (Lea Hautes Fauges), a wild and desolate tract covered with peat-bogs and heaths, themselves some 600 to 800 feet above the town. Immediately above Spa, and opposite to it, there are two other distinct hills, of lesser height, the limits of which are definitely marked out by streams or deep valleys, and these, together with the “High Moors” and their rock, constitute the leading geographical features of the immediate neighbourhood.

Examining the Cambridge sands, fresh from a remembrance of the Undercliff and the grand developement of the cherty rock of the Upper Greensand in Southern sections, perhaps its most marvellous character is that here it no longer makes a feature in the land, but has dwindled away to barely a foot in thickness, and yet is to be traced through several counties. Blending insensibly into the chalk, resembling in structure beds that sometimes occur in the Gault, it appears but as a parting seam between those deposits. Yet so soon as Dr. Fitton made clear the sequence of the Cretaceous beds, Professor Sedgwick recognised in the film of black nodules, glauconite and chalky marl, the analogue of the sands of the Vale of Wardour and the Isle of Wight.

The Junction of the Chalk with the Lower Tertiaries is nearly always marked by the presence of green-coated flints; and in East Kent, where the Thanet Sands rest on the Chalk, numerous junction-sections are exposed, exhibiting the peculiarities which I now lay before you.