December 30, 1922] 



NA TURE 



891 



The sinking of the basin thus formed appears to 

 have continued intermittently in Permian, Jurassic, 

 and Cretaceous times, the Permian and Jurassic 

 deposits in the Durham-Yorkshire area being thicker 

 than in almost any other part of Britain, and the 

 Lower Cretaceous beds (the Speeton clay), being of 

 a deep water type, contrasting strongly with the 

 shallow water and estuarine deposits of that age to 

 be found in parts of Britain more remote from the 

 basin. The chalk also reaches its maximum British 

 development on the East Coast. 



After the formation of the chalk, the area was 

 uplifted and much denudation took place prior to 

 the deposition of the Woolwich and Reading beds 

 and London Clay, which marks the commencement 

 of a further downward movement. These Lower 

 Tertiary beds still occupy the London and Hampshire 

 basins and extend below the southern part of the 

 North Sea. Prior to the great denudation which 

 followed the uplift in Miocene and early Pliocene 

 times, they doubtless occupied a much wider area — 

 the then basin of the North Sea with its embayments 

 and estuaries. 



Then followed intermittent movements of the 

 Armorican folds in the south of England, Northern 

 France and Belgium extending into Pliocene (Diestian) 

 times. 



From this time onwards it is possible to trace the 

 southern and western shores of the North Sea with 

 some degree of accuracy. In Diestian times, Harmer 

 suggests that the coast-line ran from the neighbour- 

 hood of Dover across the straits into Belgium, the 

 shore deposits being represented bv the Lenham beds 

 and the Diestian of Belgium. The later Pliocene 

 deposits indicate a gradual retreat of the sea to the 

 northwards, the fossils of the Red Crag and Norwich 

 Crag showing a gradual increase in the number of 

 living as compared with extinct species as they are 

 traced from Essex to the Wash. 



At the close of Pliocene time much of the southern 

 portion of the North Sea Basin must have been low- 

 lying land, and across this meandered the great rivers 

 of Northern Europe. The estuary of the Rhine, 

 according to Harmer, crossed Norfolk ; and in it were 

 laid down the Chillesford beds. 



To the north of the Humber the coast-line of this 

 period has been traced by a line of buried cliff with 

 accompanying beach deposits running from Hessle 

 on the Humber, inland to the west of Beverley, and 

 emerging on the line of the existing coast at Sewerby, 

 between Bridlington and Flamborough Head. The 

 plain of marine denudation in front of this old coast- 

 line has been charted and contoured by means of 

 information obtained from numerous borings which 

 have been put down in search of water in the Plain 

 of Holderness. 



The next phase was a retreat of the sea and the 

 formation of sand dunes along the foot of the cliff. 

 The geological date is indicated by the occurrence of 

 Elephas antiquus, Rhinoceros leptorhinus, and hippopo- 

 tamus in the deposits, a fauna which accompanies 

 implements of Chellean type in the south of England. 



Throughout Pliocene times, a gradual refrigeration 

 of the climate was in progress, as is shown by the 

 molluscan fossils and also by the land flora, where 

 remains of this have been preserved ; and the next 

 episode was the formation of a great ice-sheet having 

 its radiant point in the neighbourhood of the Gulf of 

 Bothnia. This appears to have displaced the waters of 

 the North Sea at least as far south as the coast of Essex. 

 Retreats and readvances took place, but the final 

 retreat of the ice can be traced with great detail 

 and precision by the drainage phenomena developed 

 along its margin up to its last contact with British 

 shores on the Ord of Caithness. 



Oscillations of level accompanied the retreat of 

 the ice and raised beaches were left, but on the com- 

 pletion of the withdrawal the land stood about 80 

 feet higher than at present. The southern part of 

 the North Sea became a marshy plain, peat bogs 

 covered much of its surface and forests clothed its 

 margins, while great rivers such as the Rhine, Thames, 

 and Weser meandered through it. 



A depression to the present level then ensued and 

 the great shallow bay of the North Sea south of the 

 Dogger Bank was formed. The sea ran up the 

 estuaries, and thus the Humber itself and its tributary 

 the Hull came into being. 



The work now being carried out by the officers 

 of the Fisheries Board is throwing much light on 

 the distribution of the various grades of material 

 accumulating on the floor of the North Sea at the 

 present time. Both the mineralogical character and 

 the size of grain of the material are being investi- 

 gated, though, of course, the latter is of more im- 

 portance from the immediate point of view of fisheries, 

 since it controls to a large extent the distribution 

 of life. 



By means of experiments with floats the direction 

 of the main surface currents has been determined, 

 and the maps exhibited by Mr. Borlev showed that 

 the floor deposits were spread out under the influence 

 of the same movements. Several different types of 

 material exist on the coast, but in each the grading 

 of the deposits, coarse to fine, is in the general 

 direction of the currents already determined by 

 other means. 



Along a great part of the east coast of Britain the 

 North Sea is at present eroding the cliffs at a fairly 

 rapid rate, and this has been measured by Mr. 

 Thompson in the case of the coast of Holderness, 

 which consists of glacial deposits. His method was 

 to take the six-inch Ordnance Survey map published 

 in 1852 and to measure thereon the lengths of all 

 easily identifiable lines running at right angles to 

 the coast, and then to measure up the remains of 

 these lines on the ground. In this manner it was 

 possible to draw the coast-line as it is to-day on the 

 map of 1852 and thus to indicate the strip of land 

 lost to the sea in the last seventy years. This strip 

 varies considerably in width in different parts of the 

 coast, there being a few points at which erosion is 

 practically nil while at others it has caused serious 

 loss. 



D 1 



New Japanese Botanical Serials 



lURING the last few decades the universities 

 and colleges of Japan have produced a large 

 number of scientific investigators, many of whom 

 have continued postgraduate training for several 

 years in Europe or America. The result is that in 

 Eastern Asia a large number of well-equipped scientific 

 investigators are now actively prosecuting research 

 and there is a danger that, working in a field still 



NO. 2774, VOL. I IO] 



far distant as regards practicable modes of com- 

 munication, their work may not be sufficiently known 

 in Europe, with corresponding loss of efficiency to 

 the workers in both continents. Japanese scientific 

 leaders are evidently alive to the danger, and the 

 reopening of extensive scientific contact following 

 the gradual cessation of war conditions has been 

 followed by the organisation and issue of a number 



