A not uncommon fossil of the Chalk, in both the upper and lower divisions, is an elongated, and more or less undulating body, composed of the scales and bones of fishes confusedly mingled one with another, and known to the quarrymen as “Petrified Eels.” Dr. Mantell was the first to discover and describe these singular objects; he says, “A long cylindrical fish, of which neither the fins nor the extremities have been discovered, is one of the most frequent, but most imperfect of the Sussex ichthyolites. The specimens are of a subcylindrical form, rather flattened by compression, from six inches to two feet in length, and about one inch wide. They occur abundantly in the Upper Chalk, and occasionally in the siliceous nodules. They are, for the most part, perfectly straight; but some specimens are undulated, as if the fish had been suddenly enveloped in the Chalk while in a state of motion. The surface is covered with small delicate smooth scales, confusedly mixed together; not one instance having been noticed in which they are disposed with any degree of regularity.”