IOWA ACADEMY OF SCIENCES. 113 



In the case of a strongly curved fold the pressure may be 

 relieved locally by sliding along the bedding plains. In others 

 the fault plane, instead of being almost vertical, may be 

 nearly horizontal, which, in the near proximity to vertical 

 faults, is apparently anomalous. 



Both the normal compound and normal horizontal faults are 

 readily reproduced experimentally. Two or three hundred 

 sheets of paper are bent in the form of a pronounced fold, and 

 clamped. The end of the fold is then covered with a colored 

 paste, that becomes somewhat brittle when dry. When the 

 clamps are slowly relieved the sheet of paste on the end indi- 

 cates at once the movements of the strata of paper, and the 

 directions and locations of the sudden movements and the pro- 

 duction of the phenomena corresponding to the dislocations. 

 On this transverse plate of paste the compound normal fault- 

 ing and normal horizontal faulting is beautifully portrayed 

 in miniature. 



A STUDY OP THE CHEMICAL COMPOSITION OF 

 SOME OF THE GRASSES OF THE STATE. 



BY J. B. WEEMS. 



One of the problems in connection with the work of the 

 experiment station for the past two or three years has been an 

 investigation of the native grasses of the state. The work has 

 been carried on by the botanical and chemical sections of the 

 station and the results which are presented here may be 

 regarded as a part of this work. The analyses presented are 

 of those grasses which have been most thoroughly investigated 

 and are as follows: (1), Dactylis glomerata (orchard grass); 

 (2), Muhlenbergia Mexicana (Mexican wood-grass); (3), Spartina 

 cynosuroides (fresh water cord grass); (4), Poa pratensis 

 (Kentucky blue grass). 



The first of these to b3 considered is Dactylis glomerata or 

 orchard grass. In the eastern states and the older settled 

 countries this grass has bean known for a long time and is con- 

 sidered one of the most valuable pasture grasses. The good 

 properties of the grass consist in being an early and rapid 

 grower and with strong resisting powers against drouth. If 

 allowed to grow to extreme height it is said to become coarse 



