August io, 1916I 



NATURE 



4S9 



Egypt for 1916 Mr. Somers Clarke describes how 

 granite boulders from which building stone for the 

 Aswan Dam was procured were dealt with by a party 

 of quarrymen imported from Baveno, in North Italy. 

 A vertical cut was made across the boulder, and it 

 was split by wedges, each group containing two 

 pairs of wedges side by side, driven into holes made 

 with steel points. Dressing was done by means of a 

 heavv metal tool, not unlike an adze, with its sharp 

 end serrated. This was let fall vertically on the face 

 of the stone, and by means of it all inequalities were 

 removed. In the same connection, Mrs. Bertha 

 Broadwood describes the method in use at the granite 

 hills in Mysore. A line of small hollows is worked 

 on the surface of the rock, a little straw is burnt over 

 the hollows, a cupful of water is poured in, and the 

 rock is thus split along the line of hollows to the 

 depth of several inches. It ma}- also be noticed that 

 "feathers," or slips, of sheet metal are in Egypt placed 

 on each side of the wedges to prevent them from 

 crushing and grinding the edfi[es of the grooves, which 

 would waste the force used in merely enlarging the 

 hole. These do not seem to have been used before 

 Roman times. 



A RECENT number of the Bulletin of Entomological 

 Research (vol. vii., part i) contains, among other 

 papers, one by Dr. A. E. Cameron describing some 

 experiments on the breeding of the man gold- fly. 

 This student has already identified this common 

 farm pest {Pegomyia hetae, Curtis) as P. 

 hyoscyami, Panz., the maggots of which often 

 mine the leaves of Belladonna and other Solanaceae. 

 He now shows that flies reared from Belladonna 

 will, in the absence of that plant, lay eggs on mangold 

 leaves, in which the maggots complete their trans- 

 formations. Curiously, flies reared from mangolds 

 could not be induced to lay eggs on the closely allied 

 sugar-beet. The dock-mining maggots belong to a 

 distinct species of Pegomyia — P. hicolor, Wied — which 

 will not lay eggs on either mangold or beet. 



i Another destructive dipteran crop pest of the British 

 Islands, the cabbage-root maggot [Phorbia brassicae), 

 which is also common and harmful in North America, 

 is described at length by A. Gibson and R. C. 

 Treherne in Bulletin 12 of the Canadian Department 

 of Agriculture (Entomological Branch). The nearly 

 allied P. fusciceps and the onion maggot {Hylemyia 

 antiqua) are also dealt with. This bulletin is impor- 

 tant for the careful records of generations through the 

 yearly- cycle and the variation in the numbers of eggs 

 laid in the diff^erent months; also for some excellent 

 photographs of the damage caused by the maggots to 

 plants. It is noteworthy that the tarred discs for pro- 

 tecting cabbage plants from egg-laying by the fly 

 are " widely used by market gardeners " in Canada, 

 whereas suggestions to try them in these countries 

 usually give rise to contemptuous amusement. The 

 iarv« of P, fusciceps eat a great variety of plants, 

 t>ut occasionally they seek a change of diet by devour- 

 [ing^ locusts' eggs. 



! Publication 253 of the Queensland Geological Sur- 

 ivey contains a description "by R. J. Tillvard of some 

 Mesozoic and Tertiary insects, mostlv collected by the 

 :hief Government geologist, B. Dunstan, who contri- 

 butes notes on the stratigraphical position. Most of 

 •-he specimens come from a thin bed in the Coal 

 VIeasures of Ipswich, South Queensland, for which a 

 Triassic age is now claimed. These represent new 

 •^"'-ra of Blattoidea (i), Protorthoptera (2), Coleoptera 

 Mecoptera(i), Protohemiptera (i), and Hemiptera 

 besides a new and interesting archaic Odonate 

 the wing of a supposed Lepidopteron (Dunstania, 

 XO. 2441, VOL. 97] 



n.g.), which, however, is perhaps more comparable 

 with such a Dipteron as Psychoda. Triassic insects 

 are little known, and we are glad to learn that this 

 is only a foretaste of what may be expected from the 

 Ipswich bed, in which the combination of archaic 

 with more modern specialised types is particularly 

 marked. From the Jurassic Wianamatta shales of 

 St. Peter's, near Sydney, are some new genera of 

 Blattoidea and Coleoptera, as well as a Protortho- 

 pteron, Mesotatan, with a forewing estimated to 

 measure 9 in. by 3 in., recalling the huge Titano- 

 phasma of the Commentry Coal Measures, and afford- 

 ing yet another instance of the persistence of archaic 

 tjpes in the Australian fauna. The wing of a Neuro- 

 pteron from the Tertiary shales of Goodna, Queens- 

 land, is referred to the Osmylidae under the new 

 generic name, Euporismites. The poor impressions 

 of a dragon-fly larva from the Tertiary or Cretaceous 

 shale of Duaringa scarcely w^arrant the introduction 

 of a new generic name, even if it were ever wise to 

 base a new genus on the larva alone. 



The New South Wales Department of Mines is 

 publishing a very elaborate monograph upon the 

 geology and mineral resources of the southern coal- 

 field, of which part i., dealing with the south coastal 

 portion, by Mr. L. F. Harper, has just been issued in 

 the form of a handsome volume of more than 400 pages 

 with numerous illustrations. The Permo-Carbonifer- 

 ous formations within the area described are divided 

 into four series, namely, (i) upper (Bulli-Newcastle) 

 coal measures, (2) middle (East Maitland or Tomago) 

 coal measures, (3) upper marine series, (4) lower (Clyde- 

 Greta) coal measures. The upper marine series has 

 not been found to contain any productive coal seams, 

 and only the first-named series has hitherto been 

 found to be of any value as a coal producer, the seams 

 of the middle coal measures being of poor quality, 

 whilst the areas of the lower coal measures are com- 

 paratively small, and the coal in them is of variable 

 quality. The workable area of the upper coal 

 measures is estimated at about 350 square miles; it 

 contains seven coal horizons, of which the uppermost, 

 or BuIH, coal seam is practically the sole source of 

 ooal supply. This seam appears to vary from 2 ft. 

 to 9 ft. in thickness, and "rolls" and wash-outs 

 appear to be numerous. The coal is of fair quality, 

 but contains a rather high percentage of ash. The 

 geology of the coal seams as exposed in the various 

 collieries is described in much detail in the memoir. 



The Transactions of the Geological Society of South 

 Africa, vol. xviii. (1916), include a long paper by ^Mr. 

 E. T. Mellor on the Upper Witwatersrand system, in 

 which a case is made out for a deltaic origin of a large 

 part of the strata. The quartzites, banded iron-ores, 

 and other features interestingly resemble those of the 

 Algonkian beds of North America. In the discussion 

 on this paper (Proc, ibid., p. 42) Prof. Schwarz 

 regards the conglomeratic layers as incompatible with 

 delta-flats, and as produced by temporary floods run- 

 ning from mountain-sides over the accumulations of 

 normally dr)^ plain-lands. 



The tern " peneplain " has undergone modification 

 in meaning, and sometimes in spelling, since it was 

 first introduced by Prof. W. M. Davis in i88g. In 

 the Geographical Review for June, vol. i.. No. 6, 

 Prof. D. W. Johnson, of Columbia University, pleads 

 for an extension, and at the same time precision, in 

 its use. He suggests writing the word "p>eneplane" 

 and using it for the penultimate stage in any cycle of 

 erosion. The word "plane" he would use for the 

 level erosion surface produced in the ultimate stage, 

 and "plain," as generally used, for a low-relief region 



