294 



REVIEWS 



the reader. Such errors, however, as ascribing Seminula argentea to 



Morton instead of Shepard, as citing a species of Leda under Nuculana 



and Leda, two genera which are recognized as being synonymous, and 



other similar instances, must be credited to the authors alone. 



It is doubtless illogical, but it is certainly true, that carelessness in 



such matters as these, in style and editorship — in brief, carelessness in 



form in which the work is presented — somehow leads the reader to infer 



carelessness in the work itself, an imputation which in the present case 



I do not believe to be deserved but which the authors might do well to 



guard against in the case of a less friendly critic. 



G. H. G. 



The Genesis of Loess a Problem in Plant Ecology. By B. Shimek. 



Iowa Academy of Science, pp. 57-64; date not given on separate, 



probably 1909. Pis. III-VII. 

 The Loess of the Paha and River-Ridge. By B. Shimek. 



Iowa Academy of Science, pp. 117-24, pis. VIII-XII. 

 These are critical papers full of important data assembled by a careful 

 observer. They bring strong support to l^ear in favor of the eolian hy- 

 pothesis of the loess. The first paper is also notable as an added recogni- 

 tion of the value of uniting the methods of two sciences in the study of 



composite problems. 



T. C. C. 



A f Ionian Sands and Gravels in Western Iowa. By B. Shimek. 

 Bulletin Geological Society of America, Vol. XX, 1909, pp. 

 399-408, pis. 33-37. 



This important paper adds much new data to the distribution and con- 

 stitution of the Aftonian formation and announces moUuscan remains in 

 addition to the mammalian fossils found recently by Calvin and the vegetal 

 remains found earlier. These remains, taken with unconformities also 

 described in this paper, made it clear that the Aftonian is a true inter- 

 glacial deposit formed under mild climatic conditions and not simply a 

 fluvial phase of the preceding or following ice-deposits. 



In a supplementary note Shimek proposes the name Nebraskan for the 

 Sub-Aftonian glacial formation because of what he deems objections to 

 the previous terms Albertan and Jerseyan and an implied objection to the 

 descriptive term Sub-Aftonian. But the facts (i) that the locality at which 

 the formation was first found and its relations first pointed out is in Iowa, 

 (2) that most of the localities now known are in Iowa, (3) that it has 



