46 American Association of Museums 



Type and figured specimens are designated, respectively, by means 

 of red stars and blue triangles, and display specimens are selected 

 either because of their relative perfection of preservation as a whole, 

 or in order to illustrate some detail of outline, nervation of structure, 

 or for the reason that they express some idea relating to evolution, 

 geographic distribution, stratigraphic type, method of preservation, 

 or some other special feature. 



The number of specimens on display is approximately 3700. Two 

 large labels in each case indicate the general geologic age of the con- 

 tents, viz., Eozoic, Paleozoic, Mesozoic and Neozoic, and the geo- 

 logic period or periods represented, viz., Laurentian, Silurian, Creta- 

 ceous, Tertiary, Modern, etc. Following are some examples of these 

 labels: 



PLANTS OF EOZOIC AND EARLY PALEOZOIC TIME: 



Laurentian, 

 Cambrian, Silurian and Devonian Periods 



PLANTS OF MESOZOIC TIME: 



Triassic and Jurassic Periods 



PLANTS OF NEOZOIC TIME: 



Quaternary and Modern Periods 



Each specimen, with the exception of the very large ones, is 

 placed upon a separate wooden block with white surface and black 

 sides and front. The front is beveled and provided with a beading 

 along the bottom to hold the specimen label. This label includes the 

 generic and specific name of the specimen; the family, order, or class 

 of plants to which it is referred; the geologic period and subdivision 

 in which it belongs, and the locality or region where it was collected, 

 viz: 



