EEPOET OF THE SECRETARY. 77 



the liiimas that preceded the Middle Caiiibiiaii fauna, Dariuj^ the year 

 he prepared a paper on the Middle Cambrian faunas of North America, 

 which was published as Bulletin 30 of the Survey series. 



Mesozoic .Division of Invertebrate Faleontologi/. — Dr. C. A. White, the 

 chief of this division, carried on field operations chieliy in Utah and 

 Wyoming. The work he planned for the season was the stratigrai^hic 

 and paleontologic study of the later Cretaceous and early Tertiary forma- 

 tions. As results of his studies in the field it is shown that a ])ortiou 

 of the fresh-water molluscau species which characterize the Laramie 

 group survived their brackish-water contemporaries and became a part 

 of the purely fresh-water molluscau faunas of the Wasatch group. 

 This indicates that there was a contiiunty of congenial aqueous habitat 

 for those mollusks from the Laramie to the Wasatch epoch, and the 

 observed character of the strata also indicates that sedimentation was 

 continuous from the one group to the other. The observations upon 

 the Jurassic strata and their fossil contents which he was able to make 

 during the past season, together with those previously made, seem to 

 justify the opinion that a large continental area existed upon the site 

 of the i)resent North American continent during the latter part of the 

 Jurassic period. An important feature of Dr. White's office work during 

 the past fiscal year was the transfer of all the fossils belonging to the 

 Survey and in charge of his division to the newly allotted space in the 

 northeast balcony in the second story of the National Museum building 

 where all the specimens were cleansed, numbered, and stored away in 

 cases for convenient reference. 



Ccnozoic Division of Invertebrate Paleontology. — On being placed in 

 charge of this division Mr. W. H. Dall's first eftbrts were directed to 

 l)utting into shape for ready reference and the identification of species 

 as they should come in, the Quaternary fossils of North America that 

 have come into the possession of the Geological Survey. The land and 

 fresh-water forms of the ancient lake basins of the West and the loess 

 of the Mississippi Valley, and the marine forms from the southern and 

 southeastern portions of the United States bordering on the sea, being 

 by far the most impoitant, the classification of these was first under- 

 taken. It is gratifying to be able to state that the large collections of 

 Quaternary fossils and allied recent forms have been suitably classified 

 and conveniently arranged for study. In the year ending June 30, 

 188G, 18,G38 lots of specimens, including not less than 60,000 individ- 

 uals, have been Libeled, registered, and put in order, about one-half as 

 much as during the whole of the previous twenty -five years since the 

 beginning of the work. A small amount of field work was done in 

 South Carolina and in Louisiana and Texas. 



Division of Paleobotany. — In the year following that for which a re- 

 port was last made. Prof. L. F. Ward devoted himself almost exclu- 



