FORMATIONS IN SOUTHEASTERN IOWA. Brit 
appears more pronounced in areas affected by brecciation and 
has not been noted as far south as St. Louis, there is a strong 
presumption that the conditions attending the formation of 
brecciated limestone exercised a controlling infiuence in effect- 
ing the transformation of the rock. The limestone of the Niag- 
ara reefs of Wisconsin are dolomitic, as indeed are nearly all 
those found in that state.t The available evidence, therefore, is 
apparently in favor of Calvin’s conclusion that dolomites are 
essentially off-shore products. 
C. H. Gorpvon. 
Geology of Wisconsin, Vol. I., p. 303. 
