106i^ Cretaceous. 



well, 16 beds of coal making- 48 feel in thickness were passed at 28 

 feet, and at 1,180 feet the sandstone of the Lower Liguitic had not 

 been pierced. He found a remarkable analogy, not to say identit^v 

 between the 547 feet of measures above the lignite beds at Evanston 

 and the conglomerate which tops the Lignitic at Colorado Springs and 

 other places. 



The masterly review of the Lignitic Group, by Prof. Lesquereux^ 

 lead him to the conclusion that it is of Eocene age. He said that the 

 Upi>er Cretaceous is positively characterized as a deep marine forma- 

 tion. Immediatel}^ over it, the sandstone shows, in its remains, the 

 result of the upheaval of a wide surface exposed to shallow marine 

 action, as indicated by fucoidal life. The upheaval coutinuing, this 

 area is brought out of marine influence to be exposed to tliat of the 

 atmosphere. It is a new land, cut in basins of various sizes, where 

 fresh w\ater is by and by substituted to brine, where vegetable life 

 of another character appears, where swamps are filling with clay and 

 floating plants, where peat-bogs in their growth form deposits of com- 

 bustible matter, etc. To suppose that the marine action is totality 

 banished from such a land would demand the absurd admission of an 

 absolutely flat surface. Of course estuaries penetrate into it at many 

 places; their waters feeding marine species, brackish shells; their 

 bayous inhabited by Saurians, and their remains mixed with leaves 

 of the trees growing on the borders and preserved together in a fossil 

 state, without impairing the true character of the formation by what 

 palaeontology considers as types of diflferent ages. The surface of the 

 Eocene sandstone, before its separation from marine influence, was, of 

 course, uneven. This sandstone has, therefore, the general characters 

 of the Eocene, while in some troughs, Cretaceous species, still living 

 in deep water, may have left their ren:iains in the sand. Even if these 

 remains were numerous, their presence does not change the age of the 

 formation. But on this subject, and in comparing our Eocene sand- 

 stone to the other groups established by geology, we find, in its abrupt 

 and permanent separation from the Cretaceous, its lithological com- 

 }X)unds, its total barrenness from animal remains, at least generally,, 

 and the homogeneity of its flora, reliable and constant characters- 

 better defined than in any geological division admitted by science. 

 This sandstone formation is inexplicable. It can be compared to 

 nothing but the millstone-grit of the Carboniferous epoch. How 

 to explain wh3^.at once, animal life seems to disappear from the 

 bottom of the sea, to be superseded by marine vegetation? May this 

 change have been caused,, perhaps, by a rapid increase of temperature 



