The following notes relating to the Kainozoic or Tertiary formations of Belgium were put together in the course of an interesting excursion through that country in the spring of 1865, in company with Mr. Hamilton, Mr. Prestwich, Captain D. Galton, Mr. W. W. Smyth, Mr. Busk, and Mr. Gwyn Jeffreys. Our route was from Harwich to Antwerp, Louvain, Hasselt, Maestricht, Liége (whence to Engis and Engihoul), Namur. Some of the party went into Brussels to see the collection in the Museum there; some to the Grotte de Han; in company with M. van Beneden I had the advantage of seeing, under the guidance of M. Malaise, the lower Palæozoic and fossiliferous rocks of Gembloux, which he considers to be of the age of the Lower Silurian series of Sir. R. Murchison. From Dinant, where we were joined by the late Mr. H. Christy, we all visited, under the escort of MM. van Beneden, Dupont, and other Belgian geologists and antiquaries, the caves of Furfooz on the Lesse. An excursion in the neighbourhood of Mons, and a visit to the coast at Sangatte, near Calais, completed the trip. Some of our party had been in Belgium before, even repeatedly. The points in its geology which on this occasion chiefly interested us were the Crag-formation of Antwerp and elsewhere, the Boldérien beds of M. Dumont, and the caves and recent researches at Furfooz. To what extent the several members of our party may concur in the views here recorded is a point