OCCURRENCES 301 



(1) Sandstone, coarse to medium, yellowish brown; beds 1 incti to 2 feet; 

 some beds of conglomerate cemented by manganiferous limouite; 

 iron concretions 8 



A ravine along the southwest side of the State road south of Guthrie 

 Center, in section 9, township 78, range 31 west, shows excellent sections 

 of higher beds. A layer of bluish gray shale 20 to 25 feet thick overlies 

 an equal thickness of fine, rather poorly sorted, light yellow, soft sand- 

 stone. The rock is finely laminated and the beds are heavy, some of them 

 several feet in thickness. Cross-bedding is abundant and dips in nearly 

 all directions except east. On the bedding planes are pebbles like those 

 in the conglomerates. 



In the east part of section 1 6 of the same township is a gravel pit in a 

 disintegrated conglomerate. There are nodules of conglomerate cemented 

 by limonite. The upper part of the deposit is of a rusty yellow color, but 

 the lower portions are gray to white. 



The base of the Cretaceous seems to rest on a surface of rather low 

 relief at an elevation of about 1,050 feet. The deposits are so very similar 

 to those of the Windrow formation that there is a decided probability of 

 their equivalence. 



The possibility of the equivalence of the Windrow formation to the 

 Eockville conglomerate of McGee (15, 16, 7) has been considered and 

 the type locality of the latter (southwest ^, northwest 14, section 24, 

 township 88, range 3 west), near Dyersville, was visited by the senior 

 author in 1919. jSTo ledge or outcrop was found, but merely loose boul- 

 ders of drift gravel cemented by limonite. The material is totally unlike 

 that of the recognized Windrow formation in the poor rounding of the 

 pebbles and the presence of igneous rocks and can hardly be correlated 

 therewith. 



MINNESOTA 



The only deposits in Minnesota which can with any probability be re- 

 ferred to the Windrow formation are the quartz pebble conglomerates 

 described by Winchell (31, 33) in Fillmore and Mower counties (south- 

 west ^, section 15, and southeast 14, section 8, township 102, range 13 

 west; north I/2, section 13, middle section 12, northeast ^4? section 11, 

 and southeast l^? section 3," township 103, range 14 west). The under- 

 lying rock is the Devonian limestone. The elevations of these localities 

 vary from 1,300 to 1,350 feet. Limonite is present only at the first 

 named, where it is known from well records. Winchell describes the 

 conglomerate as "a beautiful coarse gravel, the greater part being white, 

 often limpid quartz, the size of the pebbles varying from that of a pea to 

 that of a hazel-nut." At other places the deposits are described as "white 

 pebbly conglomerate which passes into a ferruginous grit." 



