Xo. 471] CRETACEOUS PLANT REMAINS 



191 



name was made to include several different fra<rin('iits wliicli were 

 subsequently ascertained to belong to two or more di^iiiK t -^pcc ics. 



The identification or determination of a genus soldv tn.ni tlie 

 shape or superficial markings of a cone or some of its dctachod 

 scales or of a leaf or a leafy twig, can seldom l)c entirely eonclii-ive 

 or satisfactory; but it may be readily appreciated that if, in addi- 

 tion, the internal structure of such specimens can be made out l)y 

 the use of the microscope, not only may the genera be thus deter- 

 mined beyond question, but many fragmentary scattered remains, 

 presenting no superficial characters of any diagnostic value, might 

 thus be identified and brought together into their true generic and 

 specific relationships. 



Superficial examination of the Kreischerville material showed 

 that it contained a number of recognized species, descriptions of 

 which were based upon well defined external eliaiacters, besides 

 quantities of specimens which were not identifiable bv (.rdinary 

 means. This indicated a specially favoral)le field for invotiira- 

 tion, of which advantage was taken, and the methods enij)loyed, 

 together with some of the selected results obtained, are here de- 

 scribed. 



Description of the Gross Matf.rfat. 



Botanical Characiers of the Plant Bemain,^.— \ rougii exam- 

 ination of the gross material showed the presence of pteridophytes, 

 angiosperms, and gymnosperms. The remains of the pterido- 

 phytes were exceedingly fragmentary and unsatisfactory'. Those 

 of the angiosperms consisted for the most part of dicotyledonous 

 leaf impressions in the clay, usually accompanied l)y a thin film 

 of carbonaceous matter, which generally disappeared on exiKi-ure 

 to the air. 



The remains of the gymnosperms proved to be more satisfactory, 

 however, being represented not only by isolated coniferous leaves 

 which retained more or less of the substance of the plant, but also 

 by leafy twigs and branches, cones and cone scales, and fragments 

 and logs of lignite, some of which contained amber in their inter- 

 stices. Special attention was therefore given to these remains 

 amongst which specimens of the following genera and species 

 were separated out and identified. 



