NEW KED SANDSTONE. 



opments, the whole mass of terrestrial materials was in a state 

 that may be designated as chaotic, we find here, in the first 

 stage of the second Trinity, a corresponding condition as re- 

 lating to the whole mass of atmospheric materials, and of its 

 accompanying developments as the initial steps of terrestrial 

 organic creation. Taken as a whole, however, the changes of 

 this period brought conditions on the earth's surface into 

 something like a systematic, or what may be called rudiment- 

 ally organized, form. 



5. The FIFTH development was characterized by distinction 

 of climates as prevailing in different latitudes, and by warm 

 and cold seasons, as owing to the revolution of our planet 

 around the sun ; hence, also, by new kinds of geological de- 

 posits, and higher degrees of organic life. This development 

 was comprised in the period commencing with the New Red 

 Sandstone, and ending with the close of the Chalk formation. 



The records of the general conditions of this period are very 

 distinctly preserved upon the leaves of the rocky book. On 

 the lamina) of the New Red Sandstone rocks in various 

 localities (and especially in the valley of the Connecticut 

 River), are found the distinct footprints of birds of various 

 species. These appear to have been impressed upon the sandy 

 and clayey margin of an ocean at low tide, and to have been 

 covered up by successive thin layers of sand and clay drifted 

 in by the swelling tide. On the same rocks occur marks whose 

 angles and other characteristics clearly prove them to have 

 been made by frost. They are in form exactly identical with 

 those which are now produced by frost in the mud upon the 

 borders of a stream. These appear to have been covered over 

 and preserved, in like manner with the tracks, by the detritus 

 swept in by the returning tide. But it is noteworthy that, 

 although these tracks and frost marks occur in abundance 



