TRAIJSACTIONS OF SfiCTtOJf K. 847 



Specimens which must be accepted as vindoubted Angiosperms. Previous to the 

 discovery of the supposed Angiosperms in Wealden strata of Portugal and North 

 America, the earliest record of an Angiosperm vras represented by Ileer's Populus 

 primceva from Northern Greenland. This name was applied to a fragmentary 

 specimen which may be a true dicotyledonous leaf. In 1897 Dr. White, of the 

 Geological Survey of the United States, stated that additional examples of 

 dicotyledonous leaves bad been obtained during the visit of the Peary Arctic 

 expedition to the well-known locality in Greenland where Heer's Populus 

 primteva was discovered in the so-called Kome series. From strata known as tlie 

 Atane beds, which rest on the Kome series, unmistakable -:Vngiosperms have 

 been collected in abundance. 



Another indication of the sudden increase in the number of dicotyledons is 

 furnished by the Dakota flora of the United States — in age somewhat more recent 

 than the older Potomac beds. In these plant-beds it is stated that Angiosperms 

 constitute two-thirds of the vegetation. 



We may sum up the whole matter in a few words. Tliere is some evidence of 

 the existence of Angiosperms before the close of the Wealden period. It may be 

 added that the Stonesfield Slate of England (a formation of approximately the 

 same age as the Inferior Oolite plant-beds of Yorkshire) has afforded a single 

 specimen of a leaf which in form and venation has as much claim to bo referred to 

 the dicotyledons as many of the leaves from Wealden rocks. These earliest records 

 are, however, unsatisfactory, and the names assigned to them are often misleading. 

 As soon as we ascend a stage higher in the geological series, not only do the 

 Angiosperms at once become abundant, but the whole facies of the vegetation 

 undergoes a striking change. The Gymnosperms, especially the Cycads, are ousted 

 from a supremacy maintained through countless ages, and the vegetation becomes 

 essentially modern. Many of the earlier angiospermous plants may be referred to 

 existing genera and present no features of special interest from a phyloo-enetic 

 standpoint. 



One of our most pressing needs is a thoroughly critical revision of the late 

 Cretaceous and earlier Tertiary floras, with the object both of determinino- the 

 systematic position of the older Angiosperms and of mapping out with greater 

 accuracy the geographical distribution of the floras of the world in post-Wealden 

 periods. This is a task which is sometimes said to be impossible or hardly worth 

 the attempt ; the available evidence is indeed meagre, and much of it has been 

 treated with more respect than it deserves, but it is at least a praiseworthy aim 

 not to say a duty, to take stock of our material and to compile lists of plants that 

 may bear the scrutiny of experienced systematists. We are profoundly ignorant 

 of the means by which Nature produced this new creation ; we can only empha- 

 sise the fact that in the early days of the Cretaceous era a new type was evolved 

 which no sooner appeared than it swept all before it, and by its overmastering 

 superiority converted the past into the present. 



Conclusion. 



In conclusion, I would urge the importance of taking stock of our accumulated 

 facts, and of so recording our observations that they may be safely laid under 

 contribution as aids to broad generalisations. Detailed descriptions and the 

 enumeration of small collections are a necessity, but there is danger of the student 

 neglecting the application of his results to problems of far"reachino- import 

 We may borrow a saying of a great artist in regard to attention to detail— 

 ' I see it, but I prefer to construct the synthesis.' 



There is no more fascinating task than to follow the onward marcli of the 

 plant-world from one stage to another and to watch the fortunes of the ad- 

 vancing army. We see from time to time war-worn veterans droppino- from the 

 ranks, and note the constant addition of recruits, some of whom march but a short 

 distance and fall by the way ; while others, better equipped, rise to a position of 

 importance. 



At long intervals the formation is altered and the constitution of the advancing 



