12 IOWA ACADEMY OF SCIENCES. 



the needed solution. Regarding the name "loess," however, 

 the; appropriateness of limiting the name strictly to deposits 

 of SBolian origin was urged. Since, in Iowa, the loess has 

 been derived largely or chiefly from the glacial drift, a more 

 exact terminology, distinguishing the "modified drift" from 

 loess and other deposits was believed to be necessary. Thus 

 the ' ' till ' ' when washed and assorted by water becomes ' ' mod- 

 ified drift. ' ' . The resulting gravel, the sands and the clays, are 

 distinguishable from the wind-driven or asolian deposits, 

 although the latter are largely derived from the "modified 

 drift. " Clays of the modified drift can be distinguished from 

 a3olian deposit, the true loess, and both of these from washed 

 or " modified " loess. Oxidized loess, loess loam, would seem 

 to be easily distinguisable from the typical loess. Further, 

 the relationship between the till, modified drift materials, 

 and the loess in the region of the type loess deposits of the 

 world, i. e , in the Rhine valley, were reviewed, and the simi- 

 lar relationships which have been proved to exist in Iowa were 

 recognized. Also the significance of the loess loams which 

 are usually associated with each loess formation was con- 

 sidered — and finally the scientific and commercial value of 

 these clays suggested the value of further detailed knowledge 

 as to their occurrence. 



THE PRESIDENT'S ADDRESS. 



BY THOMAS H. MACBRIDE. 



Gentlemen of the Academy: 



When, a short time ago, I was advised by our indefatigable 

 secretary that by virtue of having been chosen vice-president 

 of this body, the duty of making the presidential address fell to 

 my share, I was somewhat disconcerted. I was at first inclined 

 to push my honors from me and to say that inasmuch as no time 

 remained for the preparation of a suitable discourse, the presid- 

 ing officer would simply waive his prerogative in that particular 

 and pass to the next order of business. 



On consulting precedent, however, I discovered, what I must 

 have forgotten, that the annual address is often happily 

 employed in the simple enumeration of the scientific achieve- 

 ments of the passing year, and in suggesting lines of future 



