REVIEWS 479- 



were drained, giving rise to many smaller bodies of water. The 



remnants of some of them are still in existence. 



The bulletin will be useful to teachers and to geologists in generaL 



Good use can be made of it as collateral reading in the class room. 



It is No. I in the Educational Series of the Wisconsin Geological 



Survey and is intended for use in schools. It is an innovation in 



state survey work and will be of great help in the teaching of geography 



and geology. 



F. H. H. C. 



A Preliminary Report on a Part of the Clays of Georgia. By- 

 George E. Ladd, Assistant Geologist. Bulletin No. 6 A y 

 Geological Survey of Georgia, 1898. 

 Preliminary Report on the Clays of Alabama. By Heinrich Ries, 

 Ph.D. Geological Survey of Alabama, Bulletin No. 6, 1900.. 

 The volume on the clays of Georgia contains a general discussion 

 of clays, touching their origin, composition, properties, especially those 

 which affect their commercial value, and a discussion of the modes of 

 handling and testing clays. A chapter is devoted to the "Fall Line" 

 clays, on which the field work in preparation for the volume was chiefly 

 concentrated. The results of this field work, stated in the author's 

 language, were : " First, the tracing of the Cretaceous strata eastward^, 

 across the state, thus necessitating a modification of the geological map 

 of Georgia, which has hitherto limited the Cretaceous to a strip of terri- 

 tory, traversing the central western part of the state. Second, the dis- 

 covery of white kaolin, some of which ranks with the valuable South 

 Carolina deposits as 'paper clay.' Third, the experimental proof that 

 some of these kaolins, suitable for fire-clay, are more refractory than 

 any of the noted fire-clays of the United States." 



The clavs of the state which are found to be commercially valuable 

 are mainly in the Coastal Plain, and a sketch of the geology and physi- 

 ography of this part of the state is introduced. The clay industries of 

 the state are reviewed by localities, and some comparatives notes gath- 

 ered from other states are introduced. The excellent paper and 

 typography of the volume are to be noted as adding greatly to the 

 attractiveness and readability of the bulletin. 



The bulletin of the survey of Alabama likewise contains a general 

 discussion of clays, touching the same general points as the discussion, 



