REVIEWS. 751 



Mr. Bain's paper deals with the distribution and relations of the 

 "St. Louis limestone in Mahaska county, where it is shown to have the 

 same irregularity as to thickness and structure as it presents generally 

 in Iowa. To explain the irregularity in the surface of this formation, 

 appeal is made to erosion during Kaskaskia time, when Iowa was a 

 land surface. This would imply a considerable elevation in order to 

 produce the carving, a conclusion not wholly free from doubt. In 

 some localities a sandstone, treated as presumably belonging to the 

 coal measures, rests upon the limestone. 



The remaining paper, by Mr. Houser, is devoted to a discussion of 

 some lime-burning dolomites, and dolomitic building stones from the 

 Niagara. 



C. H. Gordon. 



