I owe my acquaintance with this interesting fossil to Mr. S. Stutterd, who kindly forwarded it to me for my inspection. It is from the Stonesfield Slate, and is preserved in limestone, but is only a cast formed in the matrix left in the rock after the organism itself had disappeared. The core had been hollow, or composed of a more speedily perishable material than the parietes, and so it rapidily disappered, permitting the empty axis to be filled with fragments of shells and calcareous sand. Externally, the cylindrical fossil is formed of sub-quadrangular peltate plates, with irregular undulate dentate margins, the projections of each of which fit into the undulations of the surrounding plates, and are arranged in linear series. A transverse section (Plate VIII. Fig. 2b.) shows each of these external plates to be the closed termination of a short tube, that has in the transverse section a hexagonal form. These tubes are filled in with a darker material, which, unfortunately, is without structure, and any determination of the affinities of the fossil must depend entirely on the external form, and the arrangement of the parts. Of necessity, these are defective and unsatisfactory materials; nevertheless, the fossil seems to me to present so remarkable an appearance, and so close an approximation to a portion of the inflorescence of an Aroideous plant, that I do not hesitate to refer it to this family; and I entertain the hope that one result of this notice and the accompanying figure may be to draw some attention to the fossil, which seems to be by no means rare, and so supply the means for more completely establishing its affinities.