MUSEUM OF COMPARATIVE ZOOLOGY. 39 



optic geology have been prepared; these labels give a brief de- 

 scription of the specimens with references to more detailed notices. 

 The first reference, of a general nature, is usually to Geikie's Text 

 book of geology, the second to a more comprehensive account. 

 The other cases have more or less complete exhibits showing the 

 organic phase of structural and dynamical geology; volcanic 

 action or vulcanism; the effects of water in motion; and glacial 

 geology. 



When possible, photographs from the Gardner Collection, 

 have been added to illustrate the specimens shown. There 

 are now 176 photographs on exhibition. 



It is hoped that the former students and friends of the Depart- 

 ment of Geology and Geography will aid in acquiring collections 

 illustrative of structural and dynamical geology and of the physi- 

 ographic features of the earth's surface, and in the adequate equip- 

 ment of this section of the University Museum. 



