SCIENTIFIC EXPEDITION TO NORTHWESTERN COLORADO 



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several alternations of land, fresh-water and brackish-water conditions, 

 under which there accumulated a thick series of alternating sandstones, 

 shales, limestones and beds of coal. We did not find the fossil plants 



and animals mingled, but each occupies definite and separate strata, 

 showing, at least locally, alternating terrestrial and lagoon conditions. 

 The palms and Corbicula indicate a climate considerably milder than 



