54 THE PALEONTOLOGY OF MINNESOTA. 



LOther OretaceoDs. 



In 1887, Mr. H. V. Winchell discovered Cretaceous shales and lignites on the Little Fork, and on 

 the Bowstring (or Big Fork) river,* but besides the foraminifers already described by Messrs. Woodward 

 and Thomas, no fossil was identified specifically. Mr. Winchell mentions "cycloid flsh scales and other 

 fossiliferous remains." 



As to the eastward extension of the Cretaceous sea in Minnesota, there is much reason to suppose 

 that it covered the whole state. In the first annual report of the Minnesota surveyt attention was 

 called to certain lignites and green clays and shales which exist in the Grand Traverse region in the Lower 

 Peninsula of Michigan, which Mr. A. D. White, of the Michigan survey of 1860, did not regard as belong- 

 ing to the drift deposits with which they had usually been classed. In 1872, soon after the writer entered 

 upon the Minnesota survey, information was sent to him by Prof. Frank H. Bradley, of a memorandum by 

 Mr. Thomas Daniels, C. E., made in 1865, purporting to describe a " half-mile outcrop of ' Eocene ' fossil- 

 iferous beds on the Nemacogin river in Wisconsin, about half way from St. Paul to Superior city, and per- 

 haps thirty miles east of a straight line connecting those places." This memorandum was sent, at his 

 request, to the late Prof. E. D. Irving; but, aside from a brief reference to it in the American Journal of 

 Science! there has been no published note of Cretaceous at that point in Wisconsin. In reviewing the 

 clays of the state of Minnesota for brick-making, in 1880, an alliance was shown to exist between the 

 alkaline blue clays, referable to the Cretaceous ingredient in them, making on burning, a cream-colored 

 brick, and the blue drift-clays of the vicinity of Milwaukee which also make cream-colored brick ; and this 

 alliance was thought to point to the former existence of a Cretaceous area in the region north from Milwau- 

 kee whence the same Cretaceous ingredient could have been supplied to the Milwaukee drift clays. At 

 Chicago, Dr. Edmund Andrews has shown that the water derived from the till, on analysis, contains a 

 greater "saline" ingredient than water from recent clays or from the surface. Theje is no Devonian or 

 Silurian shale or clay that is known to be so charged with alkaline elements as the Cretaceous beds of the 

 west to which this effect can be attributed. Quite recently Mr. B. W. Thomas has found, as stated by 

 Messrs. Woodward and Thomas in this volume (page 28), the same species of Foraminifera, in limited num- 

 bers, in the boulder-clay at Chicago, as are distributed in the boulder-clays throughout Minnesota, and 

 which are referable directly to the Cretaceous. Lastly, in studying the iron ores of the state of Minne- 

 sota, in 1889 and 1890, certain analogies were noticedl! between the Cretaceous iron ores of Minnesota and 

 certain limonitic ores of Wisconsin, allying them all together, and pointing to a common origin, thus 

 extending the waters of the Cretaceous ocean over a large area in central Wisconsin. 



Notwithstanding all these indications (which are given for what they may be worth) there is not 

 yet any known locality, between Minnesota and the Grand Traverse region of Michigan, where any actual 

 outcrop of such strata is known. 



*SIxteenth Annual Report, pp. 403, 431, 434. 



tOp. cit. pp. 110-11, 1872, 



*Op. clt. vol. x, [31.307. 



(Preliminary report on the Building stunes. etc.. of Minnesota, 1880. in the Eighth Animal Report. 



IIThe Iron Ores of Minnesota. Bulletin No. vl. 1891, p. 151. 



