254 REVIEWS 



of new data by Nathorst, Schuchert, and others. Seward, whose standing 

 and competency need no comment, makes it clear that he entertains no 

 doubt about the reaHty of such warm chmates in the regions he visited 

 and in the ages he specifies. Some of his statements are not only worthy 

 of quotation, but of emphasis: 



The cliffs on some parts of the coast are built up of limestones, sandstones, 

 shales, and old pebble beaches containing the remains of animals and plants 

 characteristic of several geological periods and clearly indicating climatic 

 conditions within the Arctic Circle much more genial than those at the present 

 day. Even in the extreme north, on the shore of the Polar Sea, limestone rocks 

 have been described by the Danish geologist, Koch, as veritable coral reefs of 

 the Palaeozoic era. 



The most northerly point at which fossil plants have been found is on the 

 east coast of Greenland, between lat. 80° N. and 81° N. Fragmentary remains 

 of plants were found by the Denmark Expedition of 1906- 1908: these were 

 described by the late Professor Nathorst, who recognized them as members 

 of a flora which preceded that of our Coal Measures. The locality where 

 these plants were found is nearer to the North Pole than any previously recorded 

 for Carboniferous plants [p. 26]. 



The fossil-bearing rocks it was our aim to investigate are exposed along 

 the shore and in the ravines of Disko and other islands and especially on the 

 Nugssuaq Peninsula. Most of them were deposited during the Cretaceous 

 period; others are Tertiary in age. Slabs of rock detached with the aid of a 

 pick-axe from the side of a ravine where the hiUs are made of a succession of 

 sheets of sediment — the sands and muds of some ancient lake or lagoon — are 

 found to be covered with the clearly outlined impressions of large leaves like 

 those of the Plane or Tulip tree, fronds of ferns hardly distinguishable from 

 species (of the genus Gleichenia) living to-day in tropical and sub-tropical 

 countries; there are also twigs of Conifers, some of which are almost identical 

 with those of the Mammoth tree {Sequoia {Wellingtonia) gigantea now confined 

 to a narrow strip of the Californian coast), and massive stems of forest trees. 

 None of the leaves preserved in the Greenland rocks have a greater fascination 

 for the student of the past history of living plants than those of the genus 

 Ginkgo. This genus is now represented by a single species, the Maidenhair 

 tree {Ginkgo hiloba) , which is sometimes said to occur in a wild state in China, 

 though it is probable that even in China and Japan, where it grows abundantly, 

 it is only as a cultivated tree associated in the oriental mind with some religious 

 symboUsm. Ginkgo is often planted in gardens and parks in Europe and 

 America and is distinguished from aU other trees by its broad and often lobed, 

 wedge-shaped leaves. Fossil leaves, some indistinguishable from those of the 

 sole survivor of this ancient genus, have been found in the Cretaceous sediments 

 on Upernavik Island (Map B), in sedimentary rocks associated with basaltic 

 lavas at Sabine Island (lat. 75° N.) on the east coast of Greenland, at several 



