232 FOSSIL FOOT-PRINTS IN COAL STRATA. [CHAP. XXXVII. 



(Tringa mimtta), which I saw running, in 1842, over the red 

 mud thrown down by every tide on the borders of estuaries con 

 nected with the Bay of Fundy. When this mud, which extends 

 over thousands of acres, has been baked by the hot summer sun 

 of Nova Scotia, it shrinks and cracks to the depth of several 

 inches or even feet, and acquires such consistency as to be divisi 

 ble into the successive layers of which it is composed, presenting 

 on many upper surfaces impressions of birds feet and cracks, and 

 on the under sides the casts of the same standing out in relief. ^ 



I have also stated f that on the sea beach near Savannah, in 

 Georgia, I saw clouds of fine sand drifted by the wind, filling up 

 the foot-prints of racoons and opossums, which a few hours before 

 had passed along the shore, after the retreat of the tide. This 

 process will account, in a satisfactory manner, for the sharpness 

 of many fossil casts of animals in ancient rocks, as the grains of 

 uniformly fine sand were poured into the newly made cavities, 

 not by a current of water, which could scarcely have failed to 

 disturb the soft mud, but by the air, which could not cause the 

 slightest derangement of the most delicate imprints. 



No less than twenty-three foot-steps were observed by Dr. 

 King on slabs in the stone quarry of Union township, before 

 mentioned, before its abandonment, and the greater part of these 

 were so arranged (see fig. 13) as to imply that they were the 

 marks of the successive foot-steps of the same animal. Every 

 where there was seen a double row of tracks, occurring in pairs, 

 each pair consisting of a hind and fore foot, and each being at 

 nearly equal distances from the next pair. The toes in each of 

 these parallel rows turn the one set to the right, the other to the 

 left. It is instructive to compare these impressions with those 

 which had previously been met with in an ancient European 

 rock (although one of less antiquity than the coal-formation), 

 namely, the new red sandstone or Trias of Saxony and Cheshire. 

 The accompanying figure (fig. 14) represents the Saxon Cheiro- 



* I have presented specimens of this red mud, with the foot-prints of 

 birds, to the British Museum, Geological Society, and Museum of Eco 

 nomic Geology. 



t Travels, vol. i. p. 167. 



