mm. Length of entire specimen, as preserved 60 Length of skull impression 18 Greatest width of same 15.5 Long diameter of right orbit 4 Transverse diameter of same 3 Transverse width of interclavicle 14 Long diameter of same 7(?) Long diameter of clavicle 9 Greatest transverse diameter 3 Length of humerus 10 Greatest diameter of same 4 Least diameter of same 1.5 Length of radius (ulna?) 11 Length of vertebral centrum 2 Width of same 3 =Genus CEPHALERPETON Moodie.= Moodie, Kans. Univ. Sci. Bull., VI, No. 2, p. 340, 1912. Type: _Cephalerpeton ventriarmatum_ Moodie. This genus is founded on remains of a nearly entire individual of a relatively large microsaurian from the Mazon Creek shales. The genus is most immediately related to the Amphibamidæ, of which two species are already known, _Amphibamus grandiceps_ Cope and _A. thoracatus_ Moodie. The present genus differs from these species in many respects, notably in size. The skull in _Cephalerpeton_ is nearly as long as half the entire body of _Amphibamus grandiceps_ Cope, inclusive of the tail. Other structural differences are the anisodont teeth, the large size and the more median position of the orbits, and the absence of the posterior tympanic notch in _Cephalerpeton_. The form of the skull recalls that of _Melanerpeton_ and _Pelosaurus_ (190) of Europe, but those genera are branchiosaurian, while the present form, from the structure of the vertebræ and the long, curved ribs, is an undoubted microsaurian. Nothing like it occurs in any of the amphibian faunas thus far made known. It is most nearly approached by a member of the genus _Erpetosaurus_, but from this genus the present form is readily distinguished by the smooth skull bones, the absence of a posterior table to the skull, and the presence of a highly developed ventral armature. The interorbital width is less than the transverse diameter of the orbit. [Illustration: MOODIE PLATE 18 1. Type specimen of _Erpelosaurus sculptilis_ Moodie, from the Cannelton Shales of Pennsylvania. Original in the University of Chicago, Walker Museum. 2. Skeletal elements of _Eryops_ sp. indet., from the Pittsburgh Red Shale at Pitcairn, Pennsylvania. _a_=nearly complete vertebra; _b_ and _c_=ribs; _d_=pleurocentrum; _f_=neural arch and spine. Originals in the Carnegie Museum at Pittsburgh. After Case. 3. Photograph of amphibian footprints, _Dromopus aduncus_ Branson, from the Mississippian shales of Giles County, Virginia. × 1/3. Courtesy of Dr. Branson. Original in the Museum at Oberlin College.