rocks in Kansas, Colorado, Arizona, New Mexico, and Utah. That during 

 these explorations he obtained from the Cretaceous strata, at a great number 

 of localities, angiosperm-leaves, consisting of some of the species obtained 

 by Doctor Hayden, with many others, all of which are described in the re- 

 port of the San Juan expedition, not yet published." 



Unhappily for paleontological science, nothing is known as yet of these 

 vegetable remains but what is said above, and they cannot be taken into con- 

 sideration now as truly representing Cretaceous species. For the reason, 

 especially, that except from the Cretaceous strata of Nebraska, Kansas, and 

 Minnesota, we do not know as yet any fossil plants positively referable to a 

 Cretaceous formation from the western territories named above, and traversed 

 by Doctor Newberry in his survey. All our plants from these countries are 

 referable to the Tertiary, like those of Colorado, Wyoming, and of California. 



In 1856, being on a tour of exploration on the southwestern limits of the 

 State of Minnesota, I remarked, above the mouth of the Big Waraju, or Cot- 

 ton-wood, which enters the Minnesota River, near the present town of New 

 Ulm, some exposures of a yellow-reddish sandstone bearing a few vege- 

 table impressions, apparently representing leaves of willow. By reason 

 of the generic identity of these leaves, I considered the rocks as of Ter- 

 tiary age. I was the more disposed to admit this conclusion, as I found 

 near by, in the bottom of the river, pieces of lignitic coal, evidently Tertiary, 

 which I supposed to have been taken out by the water, from beds underlying 

 the sandstone, somewhere in the vicinity ; for I was not then aware that in 

 the Big "Waraju, as in the Smoky Hill River and many affluents of the Mis- 

 souri and the Minnesota, these pieces of lignite coal are carried by the current 

 from the upper part of the riveiis, where they cross the Tertiary formation, 

 hundreds of miles above. 1 As I did not have then any instrument with me, 

 not even a hammer, and no means of transportation, I was unable to get 

 specimens of these fossil plants, and regretted many times thereafter the im- 

 possibility of comparing these Minnesota leaves with those of Doctor Hayden, 

 and especially with some referable to Salix, which I have since obtained in 

 abundance from Nebraska and Kansas. In 1867, at the meeting of the Na- 

 tional Academy at Northampton, Prof. Jas. Hall, who had just returned from a 

 geological exploration in Western Minnesota, exhibited, among a number of 



1 These lignites arc different from the sbaly, friable, carbonaceous matter seen in the bluffs of the same 

 river. They correspond by general aspect and chemical compound with the Tertiary lignite found, too, 

 in the bed of the Blue Earth River above Saint Peter, in the Missouri, the Smoky Hill River, &c. 



