December 21, 1899] 



NATURE 



181 



Whether the hoped-for 6000 visitors (paying, we 

 presume, a franc each) per half-hour night and day will 

 visit it and help to provide the sinews of war is another 

 matter. Norman Lockver. 



GEOLOGICAL SURVEY OF THE UNITED 

 KINGDOM.^ 



REPORTS of the progress of the Geological Surveys 

 in India and Canada have already been noticed in 

 Nature. The report of our home survey has since been 

 issued by the Director-General, Sir Archibald Geikie. 

 It is more voluminous than those of the other countries, 

 and appears rather to be a full record than a " Summary " 

 of the observations made during 1898 by the staff of the 

 Survey. Whatever may be said concerning the state of 

 our knowlege of geology in England and Wales, in 

 Scotland and in Ireland, it cannot be gainsaid that very 

 much remains to be done both from a scientific and a 

 purely economic point of view. The report before us is 

 a striking testimony to this, and when we consider the 

 limited staff and poor equipment of our Survey, it is 

 surprising how much has been done to further the progress 

 of knowledge. 



So far as the main field-work of the Geological Survey 

 is concerned, the mapping of entirely new areas has been 

 confined to the mountainous regions of Scotland and to the 

 islands of Arran, Jura and Skye ; but it is not in these 

 areas alone that fresh observations of striking importance 

 have been made. Re-surveys are being made of the coal 

 districts of South Wales, North Staffordshire, Leicester- 

 shire and South Derbyshire ; of the mineral districts of 

 Cornwall and Devon ; and of the agricultural districts of 

 the southern and midland counties. In all these cases 

 the work done actually amounts to a new survey, on a 

 larger scale than the original map, and carried out with 

 that attention to minute accuracy which nowadays is 

 absolutely essential. Revisions have also been made in 

 the Silurian areas in Ireland. 



A glance at the little index-maps which accompany 

 this report show how much field-work yet remains to be 

 done. Of the 131 sheets of the Scottish one-inch map, 

 fifty-nine only have been published. In England and 

 Wales ninety-nine only of the 360 one-inch new series 

 maps have been published. It has long been recognised 

 that for practical purposes a survey on a scale smaller 

 than six inches to a mile is of little value. The work of 

 the Survey has for many years been conducted on the 

 larger maps, MS. copies of which are deposited for public 

 reference in the Survey Offices in London, Edinburgh and 

 Dublin. In illustration of certain mineral areas and other 

 regions, a number of six-inch maps have been published, 

 but the issue of further maps was some few years ago 

 discontinued, mainly, we believe, on account of the ex- 

 pense of engraving. Cheaper processes, however, are 

 available, and it is to be hoped that the publication of 

 six-inch maps may ere long be resumed. It is not only 

 in mineral areas that these maps are utilised -they are 

 <]uite as necessary in inquiries relating to water-supply, 

 sanitary engineering, and agriculture. In these important 

 questions the highest attainable accuracy is as necessary 

 as in mining questions. Those who compare the earlier 

 published one-inch maps with the new series of geological 

 maps in England and Wales will recognise the great 

 advances which have been made in the method of map- 

 ping, and if these again are compared with the six-inch 

 maps (^.^. of the South Wales coal-field) it will be seen 

 how much work is lost or obscured in the small one-inch 

 reproduction. This difference was strikingly shown in 

 the one-inch and six-inch maps of the Durness area in 

 Scotland, published a few years ago. 



1 "Summary of Progress of the Geological Survey of the United King- 

 dom for 1898.' Pp. v-f2i6. (London: Printed for H.M. Stationery 

 Office, 1899.) 



NO. 1573. VOL. 61] 



The present " Summaiy," like the first of the series 

 which was issued a year ago, is arranged strati- 

 graphically, commencing with the Pre-Cambrian and 

 continuing to the Recent deposits ; it contains also 

 records of new railway-cuttings and well-borings, and 

 accounts of the microscopic and chemical work carried 

 on -in the Petrographical Department and of the varied 

 work performed in the Palaeontological Department. 

 Brief notice is also taken of the numerous public and 

 private inquiries made at the offices of the Survey, work 

 which increases from year to year, as help and advice in 

 reference to water-supply, soils, sites for houses, building- 

 materials, various ores and minerals, are as far as possible 

 freely given to those who seek them. 



That the field-work of the Survey must be conducted 

 on a strictly scientific basis is not to be questioned. 

 Economic results must follow, and they may not always 

 be apparent at the time of the survey. It is, however, 

 satisfactory to find that discoveries of importance have 

 been made. 



The puzzling -question of the age and origin of the 

 Highland schists continues to attract a large amount of 

 attention. The evidence gathered tends to show that 

 the "Moine-Schists" of the north-west highlands are 

 metamorphosed arkoses, sandstones, and argillaceous 

 rocks, and that there is unconformity between them and 

 the older (Archaean) gneisses. Associated with the 

 schists are several types of foliated igneous rock, and 

 these in some cases were intruded into the original sedi- 

 ments before their present foliated structures were 

 developed. The Dalradian or so-called Younger Schists 

 of the central highlands have also received much 

 attention, and structures similar to those seen in the 

 Moine Schists have been recognised in these rocks in 

 the Braemar area. What is termed the " hornfels " type 

 of alteration, producing a cordierite-hornfels, has been 

 found where the old granites, such as that of Ben 

 Vuroch, were intruded prior to the movements causing 

 schistosity. This type of metamorphism is not observed 

 in connection with later granitic intrusions, such as those 

 of Cairngorm and Lochnagar. Interesting observations 

 are rnade on the intrusions of these younger granites, 

 and it is inferred that in the case of Cairngorm the 

 mass, on its southern side, took the form of a cake or 

 sill with vertical or highly inclined edges. The meta- 

 morphic changes produced in the bordering rocks by 

 the masses of granite and by various igneous dykes are 

 fully dealt with. 



The Cambrian limestones in Skye have yielded a 

 number of fossils which connect them with the Balna- 

 kiel and Croisphuil groups of Durness. Several of the 

 species occur also in Newfoundland — and these indicate 

 a horizon below the Arenig formation. 



Analyses have been made of Cambrian dolomites from 

 Skye and Durness. 



Among the Silurian rocks in Ireland several horizons 

 have been determined by means of Graptolites and other 

 fossils. It is observed that the older rocks of the south- 

 eastern portion of that country have undergone much 

 crushing and deformation, and in the Ribband Series (of 

 Arenig age) the grit-bands are curiously broken up, 

 portions of grit having been pushed into the argillaceous 

 strata so as to produce a brecciated appearance, de- 

 ceptively like that of a conglomerate ; indeed, some of 

 these crush-breccias have actually been described as 

 conglomerates. From the Upper Silurian rocks of 

 Central Scotland a new genus of ^shes {Ateleaspis) \s 

 recorded, and also a new species of Eurypterus. 



Observations are made on the Old Red Sandstone of 

 Caithness, Ross-shire, the Lome, and South Wales. In 

 the Lome district a fish-bed has been discovered on the 

 mainland shore of Kerrera Sound, about three miles 

 south of Oban. The volcanic rocks in the Lower Old 

 Red Sandstone form a conspicuous feature in this region. 



