REVIEWS 



The Problem of the St. Peter Sandstone. By Charles Laurence 

 Dake. Bulletin of School of Mines and Metallurgy, Uni- 

 versity of Missouri, Vol. 6, No. i. Rolla, 1921. Pp. 228, 

 pis. 30. 



Professor Dake finds the St. Peter sandstone in Minnesota and 

 Wisconsin equivalent to the upper part of the Chaz}'-, and in Oklahoma 

 and Arkansas, to all of it. It is unconformable with the Potsdam sand- 

 stone in Wisconsin, and with strata above the Potsdam farther south, 

 up to the Arbuckle limestone in Oklahoma. 



A study of the characteristics of the sandstone, such as composition, 

 texture, and structural features was undertaken with a view to determin- 

 ing the origin of the sand. The author appears to have started with 

 hospitable attitude toward the hypothesis that the sand is of eolian origin, 

 but in the end he was led to the conclusion that several of the criteria 

 usually held to indicate an eolian origin for sand (i) are "of less positive 

 significance than is generally believed"; that (2) they are "significant 

 only of conditions of transportation, and not of deposition"; that (3) 

 they are "sometimes inherited from an older formation"; and that 

 (4) they are "not present in the St. Peter in any appreciably greater 

 perfection than in other sandstones of the same region known to be 

 marine." He also holds that structural features imposed on a formation 

 at the time it is laid down are "the only positive criteria as to condi- 

 tions of deposition. These criteria point rather definitely to the marine 

 origin of the [St. Peter] formation." 



Of special significance in this connection is the basal conglomerate 

 present in many places, for in it there is "no sign of wind polish or of 

 faceted forms, and nothing comparable to desert varnish" (p. 187). 



This conclusion as to the origin of the St. Peter sandstone is not only 

 interesting in itself, but seems to suggest that the "continental deposi- 

 tion" idea, long neglected, has of late been overworked. In sundry 

 recent publications it has almost seemed that if a marine origin for a 

 formation is not proved, a non-marine origin is assumed. This volume 

 is a wholesome check to this tendency. 



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