452 CARNEGIE INSTITUTION OF WASHINGTON. 



Wieland, G. R., Yale University, New Haven, Connecticut. Associate in 

 Palaontology. (For previous reports see Year Books Nos. 2-4, 6-9, 

 11-19.) 



The reports in Year Books 18 and 19, taken consecutively, outline 

 the course of cycadophyte investigation, with study of allied problems, 

 virtually as pursued during the past year. No field work has been 

 done, but considerable progress has been made in the elaboration of 

 material, both of the petrified cycads and associated and other Meso- 

 zoic gymnosperms. Among various cycadeoids closely studied is 

 the tjipe in the State University of Iowa, Cycadeoidea dacotensis. 

 The handsome and complete series of sections is of initial interest 

 and unrivaled in studies of ancient plants. A new body of fossil 

 gymnosperm material, with as broad a scope of interest as that on 

 which either of the volumes I and II of the American Fossil Cycads 

 is based, comes into view. It is not, however, to be inferred that 

 elaboration is complete, while more exact illustration is one of the 

 larger tasks ahead. 



In adequate study of cycadeoid wood structure the range of Meso- 

 zoic coniferous wood characters must be brought into fuller view, 

 and this can now be done more effectively than hitherto. We now 

 have at hand a much increased section series of woods from the cycad 

 horizons of our Northwest and also the excellent material for com- 

 parative study from South America mentioned in an earlier report. 



It is intended to extend the section series and illustrate this material 

 in somewhat better form for the botanical reader than photomicro- 

 graphs alone would permit. These fossil woods are highly variable in 

 conservation, and considerably more attention than is ordinarily 

 possible in the isolated descriptions of species must be given to bring 

 out real structure, unobscured by peculiarities of preservation. 



There are exceptionally conserved conifer stems, but the great ma- 

 jority of the stems are disappointing when first seen under the micro- 

 scope. Contrary to any first impression, the sections should always be 

 extremely well made. The study of the features of conservation in a 

 variety of specimens under the binocular shows why the greatest 

 attention should be given in bringing both surfaces of a thin section 

 down to the clearest possible polish. This being done, it is best to 

 cover the duplicates alone with thin, close covers, in order that all 

 structures may be examined under oil immersion and then drawn. We 

 can not m^ke headway in the study of the conifer woods in any other 

 way. The photographs (enlarged 50) help for the general features, 

 but do not afford the body of critical detail needed to reach final com- 

 parisons or to place relationships. Much less do photographs of 

 greater enlargement make clear enough all the salient features. 



In addition to the thin sections, the largest available well-polished 

 transverse surface section should be had. It is the belief that any 



