FOOT-PRINTS IN COAL-MEASURES. 
407 
Fig:. 437. 
Imbricated covering of j?ldn of Ar- 
chegosaurus medius, Goldf. Mag- 
nitied. 
have been three feet six inches long. The annexed drawing 
represents the skull and neck bones of the smallest of the 
three^ of the natural size. They were considered by Gold- 
fuss "as saurians, but by Herman von Meyer as most nearly 
allied to the Jjabi/rinthodon before mentioned (p. 371), and 
the remains of the extremities leave no doubt that they 
were quadrupeds, “ provided,” says Yon Meyer, “ with hands 
and feet terminating in distinct toes; but these limbs were 
weak, serving only for swimmiug or creeping.” The same 
anatomist has pointed out certain points of analogy between 
their bones and those of the Proteus anguinus; and Profess¬ 
or Owen has observed that they make an approach to the 
Proteus in the shortness of their ribs. Two specimens of 
these ancient reptiles retain a 
large part of the outer skin, 
which consisted of long, narrow, 
wedge - shaped, tile - like, and 
horny scales, arranged in rows 
(see Fig. 437). 
In 1865, several species belong¬ 
ing to three different genera 
of the same family of perennibranchiate Batrachians were 
found in the coal-field of Kilkenny in bituminous shale at 
the junction of the coal with the underlying Stigrnaria-bear- 
ing clay. They were, probably, inhabitants of a marsh, and 
the large processes projecting from the vertebrae of their tail 
imply, according to Professor Huxley, great powers of swim¬ 
ming. They were of the Labyrinthodont family, and their 
association with the fish of the coal, of which so large a pro¬ 
portion are ganoids, reminds us that the living perennibran¬ 
chiate amphibia of America frequent the same rivers as the 
ganoid Lepidostei or bony pikes. 
Labyrinthodont foot-prints in coal-measures, —In r844, the 
very year when the Apateon, before mentioned, of the coal 
was first met with in the country between the Moselle and 
the Rhine, I)r. King published an account of the foot-prints 
of a large reptile discovered by him in Korth America. 
These occur in the coal-strata of Greensburg, in Westmore¬ 
land County, Pennsylvania; and I had an opportunity of 
examining them when in that country in 1846. The foot¬ 
marks were first observed standing out in relief from the 
lower surface of slabs of sandstone, resting on thin layers of 
fine unctuous clay. I brought away one of these masses, 
which is represented in the accompanying drawing (Fig. 
438). It displays, together with foot-prints, the casts of 
cracks (a, a') of various sizes. The origin of such cracks in 
