Only a single crab (Carcineretes woolucotti Withers, Ann. May. Nat. Hist., ser. ix, vol. x, 1922, p. 535, pls. xvi, xvii; vol. xiii, 1924, p. 91, pl. iv, figs. 1–4) has so far been described from the Cretaceous rocks of Jamaica. Remains of this crab have been found in the upper part of the Rudist Limestone both at Logie Green and Trout Hall, near the Rio Minho River, Central Jamaica. Dr. C. T. Trechmann, F.G.S., has now discovered a second species of crab, Ranina trechmanni n. sp., and this was found in the shales some 40 feet below the Rudist Limestone between Cambridge and Catadupa, West Central Jamaica. The Rudist Limestone is considered by Dr. Trechmann (Geol. Mag., Vol. LIX, 1922, p. 505; Vol. LX, 1923, p. 345; Vol. LXI, 1924, p. 393) to be of Maestrichtian age, and the shales below, in which the present crab occurs, to be Campanian. This conclusion is borne out by, and to a great extent based on, the evidence of the Cephalopods described by Dr. L. F. Spath (Geol. Mag., Vol. LXII, 1924, p. 28) from the shales underlying the Rudist Limestone at Providence, Port Antonio, Eastern Jamaica, and considered by him to be of Upper Senonian and Maestrichtian age. Professor H. L. Hawkins, however, from a study of the Echinoids (Geol. Mag., Vol. LX, 1923, p. 215) does not agree that these rocks are so high in the Cretaceous as the Campanian or Maestrichtian, and considers that they have a time range from the base of the Upper Cretaceous to about the base of the Senonian.