188 REPORT OF NATIONAL MUSEUM, 1892. 



Iii the removal of so enormous a collection it will perhaps be better 

 to transfer it by orders or groups as fast as the necessary scrutiny and 

 completion of labels and enrollment are finished. It is therefore de- 

 sirable that, whenever the work is renewed, cases may be ready for its 

 reception as fast as the material arrives in Washington. 



The separation of the duplicate specimens for exchange will be simul- 

 taneous with the review aud registry of the specimens. These should 

 be labeled and fully listed before placing them in an accessible storage. 

 Several exchanges have already been engaged with American and 

 European paleontologists, the specimens for which may be selected 

 while the collection is being packed. 



In acquiring the Lacoe collection the Museum not only receives a most 

 important paleontological accession, but it becomes the custodian of a 

 large mass of unelaborated correlative material, which, if rightly used, 

 will prove of great value and aid to scientific and economic geology; and 

 this rich possession affords just ground for national scientific pride, 

 while the liberal public spirit with which it was given is worthy of 

 imitation by all patrons of science. 



My investigations of the local exposures of the Potomac formation, 

 as mentioned in my last report, were continued as opportunity afforded 

 throughout the year. In September aud October I made, in company 

 with several members of the U. S. Geological Survey, an extended 

 field trip to Texas and Arkansas with a view of determining the prob- 

 able relation of the Trinity formation of those States with the Potomac 

 formation. In April I also made another field trip, this time studying 

 the Lower Cretaceous formations of Alabama, securing a valuable col- 

 lection of fossil plants. Later, in May and June, I made an extensive 

 overland journey from the Potomac to the Raritan in New Jersey for 

 the purpose of studying the relation of the Potomac of Virginia and 

 Maryland and the so-called "Amboy clays" of New Jersey. The results 

 were iu every way satisfactory and will be published by the IT. S. 

 Geological Survey. 



Mr. Theo. Holm was the Museum assistant for the entire year. His 

 time was mainly spent in work on the herbarium, with a view to making 

 it of the greatest possible value iu the study of fossil plants. He 

 mounted and placed in the cases several hundred sheets of plants, 

 largely native trees and shrubs, and at the close of the year was 

 engaged upon the duplicate collection in selecting such as it seemed 

 desirable to mount for the study series. He had also begun the deter- 

 mination of a collection of plants from Morocco, obtained during 1889 

 by Mr. Talcott Williams, of Philadelphia. 



Prof. F. H. Knowlton continued during the year his study of the 

 Laramie flora, and had well under way at the close a revision of the 

 plants of this group, based on the original Lesquereux type specimens 

 in the National Museum and large recent collections from Colorado. 

 When this work is completed, it is hoped that the Laramie flora will be 



