FILLMORE COUNTY. 309 



Cretaceous strata.] 



two miles northwest of Spring Valley, though a drift clay with some gravel 

 is used in the manufacture of brick. A similar clay is met in abundance at 

 Spring Valley village, but it is mingled with limestone fragments and drift 

 materials. 



Besides these clayey deposits, which are believed to have resulted from 

 the degradation, or more or less perfect preservation, of the lower Cretace- 

 ous clays, there are a number of white sand deposits in the same portion 

 of the county, which probably are referable to the incoherent layers of the 

 Nishnabotany sandstone. One of these occurs north of Mr. J. W. Smith's 

 brick-yard, on sec. 17, Spring Valley. Another is situated on C. C. Temple's 

 land, S. E. J sec. 8. Bloomfield, where it is twenty feet thick at least, having 

 been tested to that depth, the bottom never having been reached. It here 

 occurs in an open prairie country, and is known to spread out over many 

 acres, lying but two or three feet below the surface. It lies on the Devo- 

 nian limestones, of course unconformably. It is not a purely white sand, 

 like the St. Peter, but yellowish white. It is sometimes very fine, but 

 varies to coarse. Another deposit of this kind is on Mr. Andrew McNee's 

 land, N. W. J sec. 22, Bloomfield, and still another on J. M. Rexford's, N. E. J 

 sec. 36, where it has been opened, as at the other points named, and used 

 for mortar. This is situated in an undulating tract, with some shrubs and 

 trees. These sand beds are not regarded as belonging to the Cretaceous 

 rock in situ, but as being copious, local products, under drift agencies, ot 

 the Cretaceous. Sometimes they embrace lumps of clay of a greenish color, 

 like the Fort Benton, and sometimes they show oblique stratification. They 

 are entirely uncemented, so as to be shoveled directly into the wagon*. 

 Another singular deposit, in the same manner referable to the immediate 

 presence of the Cretaceous, occurs in the S. W. sec. 15, Bloomfield, land 

 of Peter Peterson. Here a series of knolls, which embrace, indeed, that in 

 which is Mr. Andrew McNee's white sand pit, and are covered with aspen 

 and hazel brush, are found, many of them, to be composed of 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 hazelnut. On these 

 knolls are a few northern drift boulders, and no doubt the gravel was also 

 placed in the position it now occupies by the drift forces. This gravel, so 



Compare the Second annual report, pp. 134 and 185. 



