has fully described a large number of sedimentary origin. But since these papers were written attention has been drawn to certain fresh types of brecciated rock, and perhaps a briefer account than that in Norton's paper and one referring more particularly to British examples may be of service.A breccia may be defined as a rock composed of angular fragments united by a greater or less amount of cement, which may be similar in nature to the fragments or of a different character. The nature of the fragments may be similar or diverse.Many rocks are intermediate between breccias and conglomerates, as they contain both angular fragments and rounded pebbles. The following classification of breccias is adopted here :-I. Breccias of sedimentary origin.(1) Subaerial breccias. (a) Talus breccias. (b) Torrent breccias. (c) Cave breccias. (d) Rockfall breccias. (e) Glacial breccias. (2) Subaqueous breccias. (a) Talus and torrent breccias. (b) Residual breccias. (c) Reef breccias. (d) Bone-bed breccias. (e) Penecontemporaneous breccias including desiccation breccias.