Originally published in London by the Palaeontographical Society in 1857.

Urged by his colleague Edward Forbes, Thomas Wright (1809-84) devoted himself to completing this monograph of the echinoderms ('spiny-skinned animals') of Britain's Oolitic formations. These would be referred to as Middle Jurassic by the modern geologist. This is a notable contribution, describing as it does the echinoderms following a major stratigraphic gap. In the British Isles, apart from some minor occurrences in the Permian and Lower Jurassic, echinoderms are almost entirely absent from the Lower Carboniferous (Mississippian), a period we now know to represent 150 million years. Although common and diverse elsewhere during this interval, the British Oolitic echinoderms show many changes from those of the Mississippian. Wright's two-volume monograph includes thorough descriptions and locality details, all supported by beautiful plates. Volume 1, originally published in four parts between 1857 and 1861, considers the many and varied echinoids (sea urchins) of the Middle Jurassic.