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NATURE 



[March 29, 1894 



of Great Britain, and in particular whether any of them could 

 be separated from the rest and compared with the Lewisian or 

 Anglesea gneisses of undoubtedly pre-Cambrian age. When 

 the mapping of these rocks by the Survey was begun many years 

 age. no attempt had been made by geologists to distinguish the 

 var.ous pre-Cambrian groups of rock now known to exist in 

 Britain, and when the survey of the country was completed by 

 the mapping of Donegal, all that could be definitely stated about 

 the schists of that region was that they were in the main meta- 

 morphosed sedimentary deposits, like those of the central and 

 south-western Highlands of Scotland, of which they were 

 obviously a prolongation. No certain trace could there be found 

 of any nucleus of still more ancient rocks upon which these 

 altered sediments had originally been deposited. It was recog- 

 nised, however, that in other parts of Ireland rocks had been 

 met with in the course of the survey which presented some 

 resemblance to so-called " Archsean " masses, but of which the 

 stratigraphical relations and petrographical characters had not 

 been worked out. It was thus possible that isolated areas of pre- 

 Cambrian rocks might be detected if diligently sought for, and 

 that in this way traces might be recovered of the earliest 

 topography of the region. 



Some progress has now been made in this interesting search, 

 and successful results have been obtained, whereby the mapping 

 of the older formations has been materially improved. In the 

 west of Tyrone and the adjacent borders of Donegal a group of 

 rocks was found to present many of the typical characters of the 

 Lewisian gneiss of the north-west of Scotland. Mr. McHenry, 

 who first suggested the true nature of these rocks, was instructed 

 to map them out in conjunction with Mr. Kilroe. They were 

 found to occupy a clearly defined area and to be easily separable 

 from the schists and quartzites of Donegal which are classed with 

 the metamorphosed rocks of the south-western Highlands of 

 Scotland. Unfortunately no distinct line of contact between the 

 two groups of rock was traceable, though there could be little 

 doubt that they must be separated by a great unconformability, 

 and that the older gneiss had already acquired much of its present 

 character before the deposition and metamorphism of the younger 

 schistose series. 



Probably the most important tract yet examined is that of the 

 long ridge which runs from Sligoto Castlebar, and of which the 

 Slieve Gamph or Ox Mountains form a conspicuous portion. 

 Here Mr. McHenry has found that at the base of the younger 

 series coarse conglomerates occur, made out of the gneiss, and 

 lying apparently in violent unconformability upon the older rock. 

 If this observation is confirmed, it will establish an important 

 point, not only in Irish but in British geology. It will show 

 that the metamorphosed sedimentary rocks which form now the 

 schists that build up the central and north-western Highlands of 

 Scotland and the north-west of Ireland lie upon the uneven sur- 

 face of an ancient gneiss, which presents the characters of the 

 Lewisian gneiss of Sutherland and Ross-shire. 



SCIENTIFIC SERIALS. 



American Journal of Science, March. — Continuity of the 

 glacial epoch, by G. F. Wright. In opposition to the author's 

 view that the erosion of the rocky gorge of the Ohio river and 

 its tributaries was preglacial, Prof. Chamberlin has maintained 

 that the most important part of this rock erosion was inter- 

 glacial. The author summarises the leading facts concerning 

 the American glacial epoch by supposing that the earlier por- 

 tions of the tertiary period were characterised by low altitude 

 of land and warm temperature up to near the pole. A period 

 of slow continental elevation of the regions which are now 

 covered by glacial drift was in progress late in the pliocene 

 epoch. During this stage the fiords of northern Europe and 

 America and the extensive rocky gorges, like those of the upper 

 Ohio and its tributaries, were eroded. Owing to this elevation 

 glacial conditions characterised all the higher latitudes of 

 North America and Western Europe. The glaciated area then 

 began to sink until the land was, north of the great lakes at any 

 rate, several hundred feet lower than it is now. The channels of 

 the Allegheny, the Susquehanna, and the Delaware rivers were 

 silted up by glacial debris, but were re- excavated by torrents of 

 clear water during the re-elevation of the continent consequent 

 upon the melting of some thousands of feet of ice. There were 

 doubtless many oscillations of the ice-front both during the 

 general advance and the general retreat of the ice-sheet, but 



there does not seem to be any evidence of oscillations of the 

 front sufficient to break the proper continuity of the period. — 

 Deformation of the Lundy Beach and birth of Lake Erie, by 

 J. W. Spencer. The inferred rate of terrestrial deformation 

 in the Niagara district being i '25 feet a century, it appears that 

 before Niagara Falls can have receded past the Devonian ridge 

 near Buffalo, the drainage of the upper lakes will have been 

 turned into the Mississippi valley, which may require 7000 or 

 Sooo years. — Six and seven-day weather periods, by H. Helm 

 Clayton. The observation of barometric minima reveals many 

 instances of six and seven-day periodicities lasting several weeks, 

 and sufficiently striking to be easily recognised. In the case of 

 successive individual storms, it was found that during an interval 

 of about twenty-seven days, corresponding with a solar rotation, 

 the storm tracts were found in groups, in each of which the 

 cyclones all followed the same general direction, and were 

 separated from each other by intervals of six or seven days, or 

 in some cases by half these intervals. 



Sy Dions' s Alonthly Meteorological Magazine, March. — A wet 

 February in Edinburgh, by the Editor. In different parts of 

 Edinburgh observations of rainfall have been made for 1 16 years, 

 the wettest previous February being 5 •21 inches, in 1848, while 

 this year the fall amounted to 7 '62 inches at one station, or more 

 than four and a half times the average. — Mild winter weather, 

 by A. B. M. The writer points out that for a long time past 

 (since the beginning of the century at least) we have had a con- 

 spicuously mild first quarter of the year every twelve or thirteen 

 years. The average mean temperature for London for the first 

 quarter for 130 years, according to Buchan, is 39° '8 ; the first 

 quarter quoted is 1809, 42"''i, and the last 1884, 43°'6. Accord- 

 ing to this we might expect the first quarter of 1896 or 1897 to 

 have a high mean temperature. With the exception of the first 

 year, 1 809, the mild quarters have been followed by fine, hot 

 summers. 



L Anthropologie, tome iv. No. 6, November-December, 

 1893. — In 1891 Dr. Topinard was requested by the New York 

 Herald to give his opinion as to the qualities that should be 

 possessed by (i) the perfect >?ian, and by (2) the coming man. 

 He replied to the first question in a brief note which has since 

 been embodied, with about 150 others of a similar character, 

 in a work entitled " Ideals of Life," ly Dr. Wallace Wood, of 

 New York. Dr. Topinard now discusses the subject at greater 

 length in an article on " Certain inferences and applications of 

 Anthropology." From a natural history point of view, the 

 perject mail is he who, with the highest sense of his own 

 personality, can best adapt himself to circumstances, and 

 I possesses personal advantages which assure him, in the struggle 

 I for existence, pre-eminence over his fellows, over other species, 

 and over the agencies and powers of nature. It is he who has 

 the soundest mind in the healthiest body, and commands, 

 especially, the greatest power of estimating the importance of 

 his actions, and of making them conduce to the utmost to the 

 satisfaction of his necessities, his interest, and his pleasure. 

 P'rom the social point of view, the perfect man is he who is the 

 best adapted to that state ; who possesses in the highest degree 

 sentiments of fellowship, of justice, of altruism, of the distinc- 

 tion between good and evil, of duty, &c. which have been 

 bequeathed to him by his ancestors, and which form the 

 essential basis of our social organisation ; who regards these 

 principles as articles of faith, and makes them the invariable 

 rule of his own conduct. From the psychological point of 

 view, the perfect tnan is he whose brain is the healthiest, the 

 most philosophic, the most capacious, and the most active ; 

 who comprehends and retains the most, and who can, with the 

 best effect, draw upon his storehouse of knowledge at a 

 moment's notice. — M. Ch. Fere contributes a short note on the 

 relation of the length of the trunk to the height, in which 

 he shows that the relative proportion becomes gradually less as 

 the stature increases. — M. Salomon Reinach continues his 

 criticism of the Eastern Mirage, and discusses, in this number, 

 the influence exercised by Egypt and Assyria on the civilisation 

 of Eastern Europe.— M. G. De Lapouge describes sixty-two 

 crania taken from a modern cemetery at Karlsruhe. These 

 crania had been previously measured by Dr. Wilser, directly 

 after they had been cleaned, and very shortly after their removal 

 from the vault, and it was agreed that these two anthropologists 

 should publish the results of their observations independently, 

 so that the modifications produced by drying might be studied, 

 and that an estimate might be formed of the different results 



NO. 1274, VOL. 49] 



