REPORT OF NATIONAL MUSEUM, 1923. 91 



Work on the petrological collections has been confined almost 

 wholly to the duplicates, little of interest in this line having been 

 received during the year. Several hundred specimens were trimmed 

 and added to the lots now being accumulated for preparation of 

 school sets, and quite a number were also added to the general col- 

 lection of duplicates. These were acquired chiefly through elimina- 

 tion from the Survey sets. 



Few changes are noted in the paleontological exhibits. Here, also, 

 enlarged photographs are being introduced, nine showing the va- 

 rious physiographic provinces of the United Stales having been 

 hung during the year. Five large mounts illustrating geological 

 phenomena were added to the series assembled by Doctor Bassler 

 within the past few years, and a biologic series of fossil shells was 

 installed in a flat-top or " gem " case. Ranking first in importance 

 and interest in additions to the vertebrate exhibit is the skeleton of 

 the small lizard Sanhoa ensidens Leidy, the mounting of which was 

 completed by Gorman H. Boss with commendable artistic skill. 

 This constitutes the only articulated skeleton of a fossil lizard to 

 be found in an American museum. It was hoped that the composite 

 skeleton of an extinct buffalo assembled from the bones sent from 

 Minnesota by the John A. Savage Company, of Crosby, would also 

 have been finally placed before the end of the year, but, while the 

 restoration and mounting have been completed by Mr. Boss, the de- 

 tail of Curator Gilmore to field work prevented its installation. 



It has been found necessary to again expand the study series of 

 invertebrates. Space for this was gained by the elimination of dupli- 

 cate material, the shifting of the contents of two rooms in the base- 

 ment, and the removal of office equipment and material under study 

 from one room on the third floor to the space thus realized in the 

 basement. In this way, one entire room adjacent to the study 

 series as now installed has been gained, and space made available, 

 it is hoped, to accommodate the accessions of several years to come. 



Practically all of the time of Associate Curator Eesser has been 

 spent in the preparation and study of large collections of Upper 

 Cambrian fossils from west of the Mississippi River, turned over 

 early in the year by Secretary Walcott. The work, however, is well 

 advanced, and many of the specimens have been photographed by 

 Dr. Resser for illustration. Similar photographic work has occa- 

 sionally been done for Drs. Springer and Ulrich. 



An unusually large number of exchanges have been sent out from 

 the division of paleontology within the past year, in one instance 

 over 4,500 specimens being assembled for shipment. Both Dr. 

 Resser and Miss Beach were called on to assist in this work, but as 

 this is the only way of securing valuable and needed material, the 

 time is considered as well spent. Miss Beach has also assisted in the 



