detected that the lignitic group extended down into undoubted Cretace- 

 ous beds. My statement at that time has been overlooked, and 1 here 

 beg permission to call attention to it. In a paper published in the Pro- 

 ceedings of the American Philosophical Society of Philadelphia, dated 

 February 19, 1869, page 48, will be found the following paragraph : 



" Near Coalville, a little town in the valley of Weber River, five miles 

 above the mouth of Echo Creek, coal outcrops several times. At 

 Sprigg's opening, the dip is 20° or 30° east; and the coal-bed is about 

 fifteen feet thick, capped with gray sandstone, much of it charged with 

 pebbles. I was informed that in other places this pebbly sandstone 

 rests directly on the coal-bed. A few hundred feet from Sprigg's open- 

 ing, a shaft to strike the same bed has been sunk seventy-nine feet deep, 

 through twelve feet of gravel and sand, into black clay, that grows harder 

 downward, and contains numerous specimens of a species of Inoceramiis, 

 Ostrea, and Ammonites, showing that the black clays are certainly of 

 Cretaceous age. If these beds do actually lie above the coal, as the dip 

 would indicate, then this formation, of doubtful age, extending from 

 Quaking Asp Summit to Salt Lake, must be Cretaceous, and some of the 

 finest coal-beds in the West are in rocks of that age." 



At Bear River City I found, in considerable numbers, Inoceramus, 

 Ostrea.j and other marine forms of mollusks above the principal coal- 

 bed, which is nearly vertical in position ; but neither at Bear River City 

 nor at Coalville have I ever known of any plants being detected below 

 the lowest coal-bed. At Bvanston, about twelve miles west of Bear River 

 City, t he thickest bed of coal in the West is found, and above and below 

 it I found, in 1871, a great number of species of plants, many of which 

 have an extended vertical as well as horizontal range in the lignitic 

 group. It is plain, therefore, that the coal at Evanston is of more 

 modern age than that of the Bear River group, as shown at Bear River 

 City and Coalville, Utah. As we go southward into Soutliern Utah, 

 New Mexico, and Arizona, the greater portion of the coal-beds are in 

 rocks of undoubted Cretaceous age. It seems conclusive, therefore, 

 that the lignitic group began in the Cretaceous period in the marine 

 seas and continued on upward, through the brackish-water times, into 

 the purely fresh-water deposits. 



The illustrated volumes on the paleontology of these formations, which 

 will probably appear within a year, will doubtless define with greater 

 precision the various divisions of the Cretaceous and Tertiary groups, 

 and settle the vexed questions of age. The very elaborate and im- 

 portant volume, by Mr. F. B. Meek, on the invertebrate fossils, will be 

 ready for the press the conjing summer. The plates are now engraved. 

 The memoir of Lesquereux on the flora of the Dakota group with twenty- 

 eight plates is now ready, and he is now at work on the Tertiary flora. 

 All the other volumes are in an advanced state of preparation. 



I would call attention to the very important article in this number of 

 the Bulletin by Professor Lesquereux on the extinct flora of the Dakota 

 group ; also the article on the new species of orthoptera, by Professor 

 Thomas, and the interesting notes on the mountain-ranges of Colorado, 

 by Mr. Gardner. The elevations of the mountain-peaks, which occur in 

 the various districts surveyed by the party during the past summer, 

 will prove of great practical value. 



In Bulletin No. 1 I inadvertently omitted to include the names of 

 Robert Adams, jr., assistant quartermaster, and Mr. C. Adams, among 

 the members of the corps for 1873. 



F. V. HAYDEN, 



United States Geologist. 



