Ch. XXIL] TRIAS OF THE UNITED STATES. 453 



extreme inclination of 50 degrees is rare, and only observed in the 

 neighborhood of masses of trap which have been intruded into the red 

 sandstone while it was forming, or before the newer parts of the deposit 

 had been completed. Having examined this series of rocks in many- 

 places, I feel satisfied that they were formed in shallow water, and for 

 the most part near the shore, and that some of the beds were from 

 time to time raised above the level of the water, and laid dry, while a 

 newer series, composed of similar sediment, was forming. The red 

 flags of thin-bedded sandstone are often ripple-marked, and exhibit on 

 their nnder-sides casts of cracks formed in the underlying red and 

 green shales. These last must have shrunk by drying before the sand 

 was spread over them. On some shales of the finest texture impres- 

 sions of rain-drops may be seen, and casts of them in the incumbent 

 argillaceous sandstones. Having observed similar markings produced 

 by showers, of which the precise date was known, on the recent red 

 mud of the Bay of Fundy, and casts in relief of the same on layers of 

 dried mud thrown down by subsequent tides,* I feel no doubt in regard 

 to the origin of some of the ancient Connecticut impressions. I have 

 also seen on the mud-flats of the Bay of Fundy the footmarks of birds 

 (Tringa minuta), which daily run along the borders of that estuary 

 at low water and which I have described in my travels.f Similar 

 layers of red mud, now hardened and compressed into shale, are laid 

 open on the banks of the Connecticut, and retain faithfully the im- 

 pressions and casts of the feet of numerous birds and reptiles which 

 walked over them at the time when they were deposited, probably in 

 the Triassic period. 



According to Professor Hitchcock, the footprints of no less than 

 thirty-two species of bipeds, and twelve of quadrupeds, have been 

 already detected in these rocks. Thirty of these are believed to be 

 those of birds, four of lizards, two of chelonians, and six of batrachians. 

 The tracks have been found in more than twenty places, scattered 

 through an extent of nearly 80 miles from north to south, and they 

 are repeated through a succession of beds attaining at some points a 

 thickness of more than 1000 feet, which may have been thousands of 

 years in forming.^ 



As considerable skepticism is naturally entertained in regard to 

 the nature of the evidence derived from footprints, it may be well to 

 enumerate some facts respecting them on which the faith of the 

 geologist may rest. When I visited the United States in 1842, more 

 than 2000 impressions had been observed by Professor Hitchcock, in 

 the district alluded to, and all of them were indented on the upper 

 surface of the layers, while the corresponding casts, standing out in 

 relief, were always on the lower surfaces or planes of the strata. If 



* Principles of Geology, 9th ed., p. 203. 

 f Travels in N. America, vol ii. p. 168. 

 \ Hitchcock, Mem. of Amer. Acad, New Series, vol. iii. p. 129 ; 1848. 



