262 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



of small objects, for instance, would be quite lost in the large main 

 hall on the ground floor, although it is admirably adapted to the use 

 to which it is now put — that of an exhibit of fossil vertebrates. As 

 here described, the visitor enters this hall from the rotunda at its 

 western end, with the side halls on the south and north devoted to 

 invertebrate fossils and fossil plants. Thence one passes northward 

 into the east range devoted to physical and chemical geology. Ke- 

 turning to the rotunda once more and proceeding to the second floor, 

 the mineral collections will be found on the south side of the east 

 wing and, at the east end and on the north side of this same wing, the 

 collections of ores and other material of economic interest. Ex- 

 pressed in tabular form, and as shown by the diagrams (fig. 1 and 2) 

 the order of arrangement is as follows : 



First floor — 



Fossil invertebrates, east wing, south side. 



Fossil vertebrates, east wing, center and east end. 



Fossil plants, east wing, north side. 



Physical and chemical geology (including petrology and meteorites), east 

 range. 

 Second floor — 



Minerals, gems, and precious stones, east wing, south side. 



Economic geology, east wing, east end, and north side. 



. It may be well to state here, that the value of geological material 

 for purposes of study and research is as a rule but slightly dependent 

 upon its value for exhibition purposes. Hence it follows that a very 

 considerable proportion of the collections is stored away in drawers, 

 inaccessible to the general public, but available for study to any pro- 

 perly accredited student. The specimens thus stored away, consti- 

 tuting what is known as the study series, run numerically in hundreds 

 of thousands, or even millions if the smaller invertebrate fossils are 

 considered individually. Many of these are types, i. e., are the iden- 

 tical specimens " used by the author of a systematic paper, as the 

 basis of detailed study, and as the foundation of a specific name." 

 As long ago as 1905 there were in the division of invertebrate fossils 

 alone some 11,490 types representing 6,100 species 1 and at the pres- 

 ent time there are probably at least twice that number. Some of the 

 more important of the collections in this study series are enumerated 

 on pp. 269-271. 



DIVISION OF PALEONTOLOGY. 



SECTION OF INVERTEBRATE FOSSILS, EAST WING, FIRST FLOOR. 



In this division the exhibits are arranged in three definite series : 

 (1) a stratigraphic series, in the long continuous case along the 



1 See catalogue of the Type and Figured Specimens of Fossils, Minerals, Rocks, and 

 Ores in the U. S. National Museum, Bull. 53, U. S. N. M., 1905. 



