1897.J MICROSCOPICAL JOURNAL. 225 



The analysis was : 



Silica. 58,633 



Alumina 80,563 



Oxide of Iron (>, 186 



Carbonate of Lime. 4,263 



Magnesia 0,705 



100,350 



So it is an aluminium and iron silicate. When we 

 compare the analysis of this clay with other Infusorial 

 clay, as at Richmond, Va., Monterey, Cal., etc., and with 

 the diatom ooze of the Atlantic and Pacific oceans, they 

 are found to be essentially the same. I should style it 

 a good mineralogical species and should be disposed to 

 name it Collonite, not crystaline of course but formed 

 from the water, marine or peat, from which it was 

 thrown down. 



Microscope Slides of Vegetable Material for Use in 

 Determinative Work. 



By JOHN S. WEIGHT, 



INDIANAPOLIS, IND. 



In the determination of plants it is frequently neces- 

 sary, or at least desirable, to make examinations of 

 various organs with the aid of a lens. Seed markings, 

 glandular structures and many portions of the flower 

 upon which determinations are partly based may be so 

 minute as to necessitate slight magnification for satis- 

 factory work. For example we have in the Euphorbias 

 and Lobelias, many species in which the seeds are to the 

 naked eye mere granules, but under a hand lens, their 

 surfaces are seen lo be decidedly marked with inegular 

 ridges and pits, or are handsomely sculptured. Many 

 leaves contain glandular structures or are covered witli 

 hairs or scales which can be best seen under the len«. In 

 determining specimens on which such structures exist 

 and are of value in classification, it is often desirable to 

 compare them with like material from well detcrnuned 

 herbarium specimens. Commonly the material for these 



