842 



SCIENCE. 



[N. S. Vol. I. No. 13. 



or somewliat less than 6 per cent.; the Aquia 

 Creek beds, corresponding to the Aptian, 137 

 species or rather more than 18 per cent.; 

 the Raritan beds and their equivalents, com- 

 pared to the lower Albian, 264 species or 

 nearly 36 per cent. ; and the uppermost beds 

 of Marthas Vineyard, Long Island and 

 Staten Island, which may be called the 

 Island Series and compared to the Vraconni- 

 an, 133 species or 18 per cent. These results 

 may be put in the following tabular form : 



It will be remembered that the Mount 

 Vernon clays have been very little devel- 

 oped as yet, and when this florula is thor- 

 oughly known it will probably fully equal 

 that of the Almargem beds of Portugal, rel- 

 atively to the total Potomac flora. 



Taking the Cretaceous flora of Portugal 

 as a whole, exclusive of the Cenomanian, it 

 is found to consist of 4 algte, 1 species of 

 Isoetes, 3 of Lycopodites, 1 of Equisetum, 

 80 of ferns, 15 of cycads, 26 of conifers, 4 of 

 anomalous types, classed by the author un- 

 der the head of Proangiosperms, 18 of mo- 

 nocotyledons, 41 of dicotyledons, and 6 of 

 forms of uncertain aflSnity. 



It will be seen that as in the Jurassic, so 

 in the Cretaceous the ferns predominate ; 

 and of these, 32 species belong to the genus 

 Sphenopteris and 10 to Cladophlebis ; 7 of 

 the cycads belong to the genus Podozamites, 

 and 3 to Glossozamites. ' The conifers are 

 much more evenly distributed, there being 

 4 species of Brachyphyllum, and 3 each of 

 Sphenolepidiuin and Thnyites, while a large 



number of genera have only one or two 

 species ; among these are Abietites, Baiera, 

 Cheirolepis, Frenelopsis, Pagiophyllum, 

 PalEcocyparis, Palteolepis, Sequoia and 

 Widdi'ingtonites. The genera referred to 

 the Proangiosperms are Changarniera, Eo- 

 hrion, Yuccites, Delgadopsis and Protoi-- 

 hipis, some of which will require special 

 mention further on. Half of the monocot- 

 yledons consist of grass-like objects referred 

 to poacites, some of which he classes under 

 the Proangiosperms, and others as true mo- 

 nocotyledons. The dicotyledonous flora is 

 here well developed, but most of the forms 

 occur in the Albian. Seven species ai'e refer- 

 red to a new genus, Proteophyllum, a name 

 too near Protophyllum of Lesquereux, and 

 Proteaephyllum of Fontaine, but the forms 

 are difierent from both these ; 4 to the new 

 genus Dicotylophyllum, and 3 each to 

 Eucalyptus and Salix. 



In comparing the Cretaceous flora of 

 Portugal with that of America it is true 

 that we only find a few species that are 

 common to the two countries, really only 

 five, as follows : 



Pecopteris Brauniana Dunk. 



Sphenolepidium Kurrianum (Dunk.) 

 Heer. 



Sphenolepidium Sternbergianum ( Dunk . ) 

 Heer. 



Sphenopteris Mantelli Brongn. 



Sphenopteris valdensis Heer, 

 the last of which only occurs doubtfully in 

 the Trinity of Texas. 



Add to these Sequoir subulata, of which a 

 very near variety lusitanica, has been found 

 in the Portuguese beds. 



We should not, of course, expect the 

 species to be common to any great extent, 

 and the comparison is practically limited to 

 the genera. Looked at from this point of 

 view, we see that the resemblance is indeed 

 close, a great number of the important 

 genera occurring in both floras. There are 

 no less than 46 of these common to the two, 



