The glyptopomus minor, says M. Agassiz, found in Dura Den, and of which there is but one specimen, is possessed of a body broad and thick, approaching in form to that of the holoptychius. The fish is lying on the belly, and turned slightly to the left, so that it is the back and right side which are represented in the plate. The head is proportionally small, covered with bones very irregularly carved, presenting a dense and diversified granular aspect. On the side of the head there is a large enameled plate, which shows that the cheek was covered, as in the polypterus, with one single osseous plate, on the under edge of which was fixed the large masticatory muscle. The scales on the body of the fish are large, high on the sides, and nearly square on the back, where in the middle they form an oblique series converging to an acute angle. The scales are very thick set on the side of each other, and apparently connected only by means of the skin to which they are attached. The enameled surface is not smooth, but rather marked with a fine granulation, which imparts a rich velvet gloss to the scale. Traces only of the fins are preserved, partly of the ventral, partly of the dorsal or caudal, and the rays of which are all apparently short and slender. This specimen forms a part of the author’s collection, but inadvertently described as belonging to that of Professor Jameson. Another genus, established from the fossils of Dura Den by M. Agassiz, is the Pamphractus, of which there are two species, _Hydrophilus_ and _Andersoni_. These are both in the collection of the author, and have a special history of their own, from which, when read in all its details, it would appear they have suffered as roughly at the hands of geologists in simply determining their class, order, or genus, as they ever did from the physical revolutions amidst which their lot was originally cast.