BERRY: SPECIES REFERRED TO THINNFELDIA 439 
others,* I should say that they are correctly classed among the 
Filicales. 
The American species which have been referred to this genus 
embrace two distinct types of plants. Those from the older Cre- 
taceous beds of Potomac age and from the Triassic apparently 
represent true ferns comparable with the European type, and since 
the genus as properly restricted is an oid one, not appearing else- 
where after the close of the Jurassic (except for the doubtful 
Thinnfeldia variabilis Velen.) the American Cretaceous species of 
Fontaine may be regarded as the dwindling remnants of an older 
flora (only one of his species is at all common or occurs outside of 
Virginia), thus forming one of the many surviving elements in the 
Potomac flora that gave it such a decidedly Rhaetic facies. It is 
quite otherwise with the middle and upper Cretaceous species 
which have been referred to the same genus. They are all much 
larger-leaved plants and some of them have a wide distribution. 
The remains in themselves are unmistakably characteristic, although 
their true botanical affinity is perhaps not so plain; superficially 
there is considerable resemblance to the polymorphous filicalean 
genus Sagenopteris from the older Mesozoic of this country and 
Europe, but this resemblance is only superficial. 
Each describer has doubtingly referred his specimens to Z/hinn-~ 
Jeldia as a matter of convenience or precedent rather than from 
any conviction of relationship with the species from the older 
formations, and all have noted their resemblance to the existing 
species of Phyllocladus. JI have made careful comparisons with 
the living material available at the New York Botanical Garden 
and am thoroughly convinced that all of the mid- and late Creta~- 
ceous species should be included in the coniferous family Taxaceae. 
They may perhaps form a link between the Podocarpeae and the 
Taxeae, and while they are unmistakably related to Phyllocladus 
their extremely large size compared with the existing members of 
that genus and other minor differences such as petiolate forms and 
the general absence of crenate margins make it desirable to refer 
them to a new genus which while indicating their proper relation- 
ship shall keep them distinct from the existing small-leaved species. 
This genus may be designated Protophyllocladus, and such additional 
*Fl. Dak. Group, 34. 
