Carriacou, the largest of the Grenadines lying between Grenada and St. Vincent, is the only one, so far as is known, of that group of islands which is not predominantly volcanic in origin. It may be described as the only limestone, or largely limestone, island in the whole inner arc of the Lesser Antilles which comprises Grenada, the Grenadines, St. Lucia, Martinique, Guadeloupe (west half), Montserrat, Nevis, St. Kitts, St. Eustatius, and Saba. Carriacou is 6¾ miles long and 2⅓ in greatest width and at High North Hill and Chapeau Carré rises to 980 and 960 feet. The remainder of the island is rugged and has several lesser peaks and a central ridge, running roughly north to south, 600–830 feet in height.

Recently the author has been investigating the sequence of floras and faunas in the Warwickshire Coalfield. In the course of this work particular attention has been given to the flora of the barren Upper Coal Measures, which, according to Eastwood (1923, p. 42), includes the Keele Series and at least 1,700 feet of the Corley or Enville Series. Vernon, on the other hand, placed the latter in the Permian (1912, pp. 590, 603), and he noted that the Corley Series rests unconformably on the underlying Upper Carboniferous strata. Shotton, however, stated (1929, p. 169) that in this area he could see “no evidence for any Permian System (in the sense of System being separated from the Carboniferous by an unreprented time-interval)”.