302 THWAITES AND TWENHOFEL THE WINDROW FORMATION 



In Goodhue County (11, 31) are exposures of clays and sands with 

 associated conglomerates at elevations of 1,050 to 1,150 feet. Some of 

 the sandstones contain fossil leaves which have been referred to the Cre- 

 taceous. The deposits are believed by Sardeson (21) to have been gla- 

 cially transported from another locality. There is no good evidence con- 

 necting these deposits with the Windrow formation, 



ILLm^OIS 



Salisbury and others (20, 21, 29, 31, 35) mention occurrences of gravel 

 in Illinois and suggest their probable equivalence with the gravels of the 

 Windrow formation. Some of them rest on the tops of ridges, and these 

 may be of the same origin and age as the Windrow formation. Others 

 appear to be merely preglacial stream terrace deposits. The available 

 published information is not sufficient to enable the authors to decide 

 which of the occurrences may be of the same age as the Windrow forma- 

 tion. The elevations of none of these localities greatly exceed 700 feet. 



OTHER STATES 



Salisbury (20, 21) mentions high-level gravels in Missouri, Kentucky, 

 and Arkansas, which he thought might be correlated with the Devils Lake 

 deposit. The junior author has seen a few occurrences of chert and 

 quartz pebbles on the hilltops of Kenton County, Kentucky, and this 

 material is very like that in the Windrow formation. 



Fossils 



No fossils have been discovered in the Windrow formation which are 

 of the same age as the deposit, unless the conglomerates and associated 

 deposits in Guthrie and Carroll counties, Iowa, in which leaves of Meso- 

 zoic aspect have been found and the Goodhue County, Minnesota, clays 

 which contain Cretaceous leaves belong to. the formation. Fossils of 

 older formations are common in the chert pebbles. 



In Wisconsin fossils have been collected at four localities. Their oc- 

 currence at Devils Lake has long been known. The writers have found 

 them at Tunnel Number 3, Summit, and Windrow Bluff. 



Salisbury (21) lists the following forms from Devils Lake as identified 

 by E. C. Quereau : 



Astrocerium venustum Hall, Niagaran. 

 Zajihrentis cf. turMnata Hall, Niagaran. 

 Callopora elegantula Hall, Niagaran. 

 Retopora sp., Niagaran. 

 Orthoreras junceum Hall. Galena-Trenton. 



