uplift known as the San Rafael Swell, in Castle Valley, as being 

 possibly of laccolitic origin, though, as it had not been studied^ 

 its character is problematical. The nature and occurrence of the 

 phenomena of laccolites, as described by Gilbert in his "Geology 

 of the Henry Mountains," was explained. 



Prof. Trelease exhibited a specimen of the plum-like fruit of the 

 maiden-hair tree {Salisburia adianti folia), and remarked on 

 its structure saying that this was the first instance in which the 

 species had been observed to fruit in St. Louis. The specimens 

 were obtained from a tree, not far from fifteen years old, grow- 

 ing in the Missouri Botanical Garden. The species is dioecious, 

 and for this reason many trees are sterile ; but pistillate trees 

 have been noticed to fruit for some years past at Central Park, 

 New York city, and about Philadelphia. 



Prof. Trelease also laid on the table two specimens of so-called 

 jumping-beans, which had been sent to Mr. Henry Shaw by a St. 

 Louis lady. These specimens, which he thought were similar to 

 others that had been shown on previous occasions by Prof. Riley, 

 were shown to be the carpels of a euphorbiaceous fruit ; and, on 

 opening them, the motion manifested was shown to be due to a 

 lepidopterous larva which had effected an entrance while young, 

 and had eaten the developing seed. After giving a brief resume 

 of the literature of the subject, Prof. Trelease mentioned the seed- 

 like oak-galls, sometimes known^as jumping-seeds, which are 

 singularly moved by the larvas they contain, and touched briefly 

 upon the power of locomotion possessed by certain grass-fruits, 

 such as the "animated oats," the fruit of sweet vernal grass, etc. ; 

 as well as the self-burying fruits of erodium, stipa, certain species 

 anemone, etc., showing that in these cases the power of movement 

 resides in the fruit or its appendages, and is useful in disseminat- 

 ing or planting the contained seed. 



Adjourned. 



December 7, 1885. 



The Academy met Monday evening, Dec. 7th, 1885, at the 

 Academy rooms, President Nipher in the chair, and Messrs. 

 Hambach, Trelease, Adams, Tivy, Leete, Seddon, Foote, Wheel- 

 er, Smith, and Engler, present. 



