Henry Woodward (1832–1921) intended this monograph, originally published as two parts in 1883–4, to be the first of a series of supplements aimed at completing Salter's unfinished work on British trilobites. In the event, no others were published. As the first monographic treatment of Carboniferous trilobites from Britain and Ireland, it has remained a standard work. Thirty-one species distributed among four genera are described, including the type species of the well-known Phillipsia, Griffithides and Brachymetopus. The specimens are faithfully reproduced in a series of fine illustrations. The monograph concludes with three short appendices: the nature of pores on the trilobite headshield; a new Carboniferous trilobite from Ohio; and a letter from Agassiz on possible affinities between trilobites and a marine isopod. Woodward described further new species of Carboniferous trilobites in a series of papers published between 1884 and 1906, which acted as supplements to his monograph.