68 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. I. 



ters of the foot are clearly developed, with its rows of pha- 

 langes, and its claws, and integuments. So far as my obser- 

 vations extend, the sharpest impressions are on the shales of 

 the finest texture, with a smooth glossy surface, such as would 

 retain the impressions of rain-drops (as in Lign. 21). The 

 layers of stone do not often present this kind of surface; but 

 recently I have discovered a stratum containing in all more 

 than one hundred most beautiful impressions of the feet of 

 four or five varieties ; the whole surface having also been 

 pitted by a shower of rain. The impression of a medallion 

 is not more sharp and clear than are most of these imprints ; 

 their remarkable preservation may probably be ascribed to 

 the circumstance that the surface of the stratum was in- 

 crusted with a layer of micaceous sandstone, which adhered 

 so firmly that it could not be removed without the laborious 

 and skilful application of the chisel. The appearance of this 

 glossy layer, which is of a grey colour, while the slab is of a 

 dark red, seems to indicate that it was washed or blown over 

 the latter while in a state of loose sand ; thus filling up the 

 foot-prints and rain-drops, and preserving them unchanged 

 in the smallest particular ; the form of the nails or claws, 

 and joints, and the deep impressions of the distal extremity 

 of the tarso-metatarsal, or shank-bone, being exquisitely dis- 

 played. The great slab (Lign. 22), which is about six by 

 eight feet in dimensions, and two inches in thickness, contains 

 above seventy-five impressions. There are five rows of the 

 species called by Professor Hitchcock Ornithichnites fuli- 

 coides? of five and six foot-marks each; three rows of the 

 medium size, of four imprints each ; one row of the small 

 size, of fourteen consecutive imprints; besides several others, 

 ranging from two to six impressions each. It is worthy of 

 remark, that of these numerous footprints, with but one or 

 two exceptions, two or more nowhere occur on the same spot." 

 The direction and disposition of these footsteps on the 

 largest stone are shown in Lign. 22 ; and lines are drawn 

 from one imprint to another in the course of the consecutive 

 tracks, to render the illustration more intelligible. The 

 principal tracks on this slab are as follow ; viz. 



1 O.fulicoides, so named from the resemblance to the footprints 

 made by the recent Cinereous Coot (Fulica Americana). See " Trans. 

 American Geologists," p. 259, 1 vol. 8vo. Boston, 1843. 



