Some very interesting deposits of Pleistocene age have lately been exposed on the Burton Road, Derby. The road rises on the north side of Mill Hill, and near the top, at the height of 260 feet, cuts into a mass of Boulder-clay, which is, or was, well shown in the cuttings for the new roads leading into Byron Street. Another outlier of the same clay is exposed in Littleover Lane to the southwest. The main mass of the deposit cut into on the Burton Road is a red morainic clay with boulders; apparently a subaerial moraine subsequently modified by the passage over it of land ice. Unlike the tough, silty, red and blue aqueous Boulder Clays so plentifully spread over the Midland counties, it shows little or no signs of aqueous action. Sometimes it has a banded or streaked appearance, but this seems to be due rather to a crushing or pressing-out action than to original conditions of deposition.

A Very important discovery was made independently by Mr. Davison, and somewhat earlier by Mr. T. Mellard Reade, when they demonstrated that, on the hypothesis of the earth having cooled as a solid body, there is within it a certain level, which is called by Mr. Davison the “ surface of zero-strain,” and for which Mr. Reade has adopted the term “ level of no strain.” At this level compression ceases, and for a certain distance beneath it extension, or stretching of the layers of the globe, takes the place of compression.

On De La Beche's Geological Survey Map of Cornwall are three colours representing the associated rocks at, and on each side of the Manacle Point. The Point itself and for a considerable distance south of it is represented as a greenstone. Partially encased in the greenstone and to the south of it is gabbro, which forms the main mass of this rock in the Lizard district. On the north side of the greenstone which forms the extreme south wall of Porthonstock Cove is hornblende-schist, which with some serpentine and other rocks terminates against the killas, or slates near Porthalla.

Several observers with seeming good reason have drawn attention to the fact that the greenstone as represented on the map is made to cover much too large an area to the south, and that any one walking from this direction, or the reverse, finds gabbro where the former rock was expected to occur.