May 26, 1921] 



NATURE 



407 



sive tract of undeveloped reservation land within the 

 United States. This area forms the subject of a 

 geographical and hydrographical reconnaissance by 

 Mr. Gregory, whose report is embodied in Water 

 Supply Paper No. 380. 



The exploration of a little-known region has con- 

 siderable attractions for the adventurous, and Mr. 

 Gregory in a personal introductory note confesses to 

 Its powerful appeal. The Navajo country, he points 

 out, contains the remnants of an almost extinct race 

 whose long occupation of the district is recorded in 

 ruined dwellings and abandoned fields. It is true that 

 roads have been established along selected routes, but 

 by far the larger portion of the territory is accessible 

 only by trails, and in the rougher areas no recognis- 

 able tracks are to be found. 



The country contains many extremely interesting 

 features, topographical, geological, and hydro- 

 graphical. The 200 pages of the report are replete 

 with valuable notes on the natural resources of the 

 district, and indicate a careful and painstaking inves- 

 tigation. Topographically, the country forms part of 

 the Colorado plateau, a region of flat-lying or slightly 

 tilted rocks, cut by canons and surmounted by mesas 

 and buttes. " So numerous and so closely interlaced 

 are the canons in some portions of this singular region 

 that they have displaced all but scattered remnants of 

 the original plateau, leaving narrow walls, isolated 

 ridges, and spires so slender that they seem to totter 

 on their bases, shooting up to an enormous height 

 from the vaults below." 



The most inaccessible, least known, and roughest 

 portion of the reservation is a region of bare red 



sandstone rock forming a plateau, known as the 

 Rainbow Plateau, intersected by innumerable canons, 

 some of which are bridged by natural arches. One of 

 them is a symmetrical semi-circular curve with a span 

 of 274 ft. It gives its name of "The Rainbow " to 

 the plateau. 



The Navajo Indian is giVen a fairly good character ; 

 he is vigorous, intelligent, and capable of hard work 

 provided it be not too continuous. He is, however, 

 independent towards those who engage his services, 

 ' and liable to take himself off. " He will help him- 

 i self to interesting trinkets and to food, but may be 

 trusted with valuable things and with important 

 missions." 



The report is well illustrated by photographs and 

 maps. 



(3) Big Smoky Valley, the subject of Water Supply 

 Paper No. 423, is a typical Nevada desert valley — a 

 plain hemmed in by mountain ranges and underlain 

 by porous rock-waste eroded therefrom. It once con- 

 tained two large lakes, one 40 miles long and g miles 

 in maximum width in the upper part of the valley, 

 and the other about 22 miles long bv i^\ miles wide 

 in the lower part. The depth of the former ranged 

 to as much as 170 ft., and of the latter to 70 ft. The 

 existence of these lakes is deduced from shore features 

 which are still in existence. The climate is distinctlv 

 characteristic of an arid tract, the annual rainfall 

 being generally about 6 In. or 7 in., or even less. 

 The valley is but sparsely populated, and the 

 settlers are principally engaged In mining or mill- 

 ing. The report contains maps, diagrams, and 

 photographs. 



The Plaice Fishery in the Belt Sea and Neighbouring Waters.^ 



'X*HE sea-fisheries of Great Britain, though perhaps 

 -*- of less importance to the prosperity of the 

 country than the supply of coal, are nevertheless of 

 vital interest in more ways than one. Consequently, 

 anything bearing on the problems connected with 

 them, especially as to their permanence, ought to 

 awaken interest in all who have practically studied 

 this intricate subject, as well as to arrest the attention 

 of the legislators and the public. Few nations have 

 done more in proportion to their populations than the 

 Danes in unravelling various problems of the sea- 

 fisheries, and were it only for the single case of the 

 remarkable life-history of the eel as elucidated by 

 Dr. Jobs. Schmidt, their labours merit careful attention 

 as well as commendation. 



The Report of the Danish Biological Station for 

 1920, by the experienced expert Dr. Petersen, who is 

 well known in fisheries researches and for trans- 

 planting so successfully the plaice into the Limfjord, 

 discloses a new feature in the plaice-fishery of the 

 Belt Sea and neighbouring waters. No fish in the 

 North Sea, indeed, has given more solicitude to 

 scientific investigators and the fishing industry than 

 the plaice, which, after the twenty years' labours of 

 the International Fisheries Council, was sinecled out 

 as the only form requiring legislation. Dr. Petersen, 

 the author of the Danish report, hitherto has held 

 the belief that It was possible to produce impoverish- 

 ment of certain areas by over-fishing, though at the 

 Dundee meeting of the British Association in 1912, 

 when " Impoverishment " was challenged, he declined 

 to give an opinion, nor did anyone present support It. 

 Dr. Petersen, indeed, had in former years pointed out 



1 " On the Stock of Plaice in Relation to the Intensive Fishing of the 

 Present Times in the Belt Sea and other Waters." Report of the Danish 

 Biological Station to the Danish Board of Agriculiurc, xxvii., 1920. By 

 Dr. C. G. J. Petersen. (Copenhagen: G. E. C. Gad, 1921.) 



NO. 2691, VOL. 107] 



the decline of a Danish plaice-fishery, but, as Dr. 

 H. M. Kyle afterwards proved, that was a mis- 

 apprehension. Now in this report of 1920 we have 

 the remarkable admission that the Intensive plaice- 

 fishing, first by gill-nets and then by seines with otter- 

 boards (which increased greatly from 19 12 to 19 19) 

 worked from motor-boats In the Belt Sea and neigh- 

 bourhood, has resulted, not in the impoverishment 

 of the area, but In the more rapid growth of the 

 plaice of to-day. The plaice now fished are younger, 

 larger, and better fishes than formerly, though they 

 are fewer on a given hectare, but the yearly yield is 

 larger. Further, in the words of Dr. Petersen, "the 

 plaice got formerly we did not care to eat . . . now 

 we regard them as delicacies." 



Dr. Petersen supports his views by the Fiskerel- 

 Beretnlngs statistics for twenty years, which show 

 that this intensive fishery has had the effect of In- 

 creasing the weight of plaice from an average of 

 5 kg. per score to 10 kg. per score. The original 

 4ense old stock has been fished out, and a new, 

 quick-growing race, fewer in number per hectare, has 

 fortunately appeared. " It is like a lawn which is 

 cut many times a year in lieu of once every second 

 year ; the latter method produces old, bad grass only, 

 the former gives much more and better grass, but 

 calls for much more work." Instead of 500 tons 

 before 1900, the fishery of the area now produces 

 1000 tons; Indeed, in 1912, 1913, and 1919 the yield 

 was about 3000 tons, and valued at 3,000,000 kroner. 



In 1900 the fishing In the Great Belt at 22 m. 

 produced many undersized plaice amongst the larger 

 forms of 40 cm., and there was a majority of males. 

 In 1920 there were few undersized forms, and 

 generally they were larger and heavier than before, 

 the larger being similar to the larger in 1900, and 



