In the course of work in collaboration with Dr. J. E. Hemingway on the petrography of the Dogger of North-East Yorkshire it has been found that brookite is widely distributed as a “heavy mineral” constituent in several different kinds of sediment. This is in agreement with results obtained earlier by myself alone in the study of sandstones from higher horizons of the Middle Jurassic in Yorkshire. Although it does not yet appear that the distribution of brookite in the Dogger is of any particular significance, nevertheless the mineral itself shows interesting peculiarities and variations; a detailed discussion of these would be out of all proportion in the paper which we hope to publish shortly on the character and distribution of the Dogger in general; and it has therefore been decided to give here a brief and mainly mineralogical account of the different varieties of brookite met with, without discussing the general problem of the abundance of titanium minerals in the Yorkshire Jurassics and their local distribution.