liiriiir of Recent Geological Literature. 329 
per Cretaceous beds of Patoot, Greenland, in which 17 Dakota species 
are found; and 12 Dakota plants occur in the Amboy clay of New 
Jersey. 
The Dakota flora comprises 6 ferns, 12 cycads, 15 conifers, 8 monocot- 
yledons and 129 dicotyledons; while the schists of Atane have yielded 
i>l ferns, 8 cycads, 27 conifers, 8 monocotyledons and 197 species of di- 
cotyledonous plants. The greater abundance of ferns and conifers in 
Greenland was probably due, as Lesquereux suggests, to the difference 
of some thirty -five degrees in latitude and the probably moister and 
cooler climate at the north. Although the oldest known traces of di- 
cotyledonous species are the leaves of poplar trees in the Cretaceous 
schists of Kome, Greenland, next underlying the Atane beds, this class 
of plants multiplied very rapidly so that in the next epoch they gener- 
ally covered the land and doubtless formed extensive and majestic for- 
ests. The Dakota fossil leaves were evidently derived from trees and 
shrubs growing close on the borders of marshy tracts, or, perhaps, on 
alluvial lands occasionally overflowed, where they were buried and fos- 
silized. They are generally found flattened in the planes of sedimenta- 
tion, being neither crumpled, rolled nor lacerated: and sometimes all the 
leaves of one locality belong to a single species, while at a short dis- 
tance another group of leaves represents other species, genera or even 
families. The author reached the conclusion, from the study for this 
volume, that ''the flora of North America is not, at the present epoch, 
and has not been in past geological times, composed of foreign elements 
brought to this continent by migration, but that it is indigenous." 
It is stated by the editor that scarcely any changes in the manuscript 
were made, beyond such as were called for by Prof. Lesquereux's notes, 
written during his examination of the new Kansas collections, w 7 hich 
occupied the closing year of his life, so far as strength remained for 
scientific work. Mr. Knowlton also appends a notice of the life of Les- 
quereux, with an autobiographical letter addressed in 1881 to Prof. L. 
F. Ward, and an extract from Prof. Edward Orton's biographical article 
in the American Geologist of May, 1890. 
Gasteropoda and Cephalopoda of the Raritan clays and Greensaml 
marls of New Jersey. By Robert Parr Whitfield. Monographs of 
the U. S. Geol. Survey, vol. xviii, pp. 102, with 50 plates and 2 figures in 
the text. Price, $1.00. Washington, 1892. This report of work done 
for the Geol. Survey of New Jersey supplements the previous volume 
by the same author which forms the ninth in this series of monographs, 
treating of the brachiopods and lameliibranchiatesof these formations. 
The fossils described in both volumes exist chiefly in the form of casts, 
except in the case of the cephalopod shells of which many fragments 
are obtained. It has been, therefore, a task of unusual difficulty to de- 
termine the species and prepare their illustrations. Besides the species 
which are described and figured, numerous others are in tco imperfect 
condition to permit publication. 
The strata yielding these shells have been denominated, in ascending 
