296 



NATURE 



[January 24, 1901 



analogous in character to those which appear in the 

 north-west portion of the Glarus-Prattigau crust-basin. 



The Falknis block is an anticlinal block separated by 

 curved strike-faults from the Rhatikon on the north and 

 he Prattigau on the south, and cut by north-south faults. 

 It shows, therefore, the general east-west strike and 

 transverse fractures characteristic of the eastern Alps. 

 The curvature of the strike in the west part of the 

 Falknis Chain from east-west to north-west may, like 

 the curvature of the fault at this part, be taken to signify 

 a resultant or compensatory divergence due to the inter- 

 crossing of the local and the east-Alpine strike. Similarly, 

 at the east end of the Falknis, the east-west strike curves 

 to the south-east. The Falknis fault-block is a replica 

 of the Groden Pass anticlinal fault-block. The east-west 

 strike is the dominant strike of the Eastern Alps, 

 trending to E.S.E. in South Tyrol. It is acknowledged 

 to have been an ancient strike along which movements 

 have recurred in various ages in the Eastern Alps, 

 although during the Pliocene movement the horizontal 

 compressions from north and south were much less 

 intense in the eastern than in the western Alps. This 

 fact expresses the chief difference which obtains between 

 the structures on the east and the west of the Rhine 

 Valley. The fold-arcs round the east of the Glarus- 

 Prattigau crust-basin have not sustained the same degree 

 of compression during the subsequent Alpine folding as 

 those round the western periphery ; neither have the 

 horizontal pressures acted quite from the same directions, 

 the Alpine pressures having acted across Glarus towards 

 the N.W., and across the Prattigau and Rhatikon more 

 towards the north. 



The eastern thrust from the Silvretta Massive gives 

 expression both to the horizontal compressions rectangular 

 to the eastern fold-arc of the local crust basin, and to the 

 horizontal strains acting along the strike of the Alpine 

 curve. In the greater Alpine curve, just as in the case 

 of the smaller curve of the local basin, the formation of 

 radial uplifts and downthrows is determined by these 

 tangential pressures. And it is this cross-system which 

 is more particularly accountable for the diagonal N.N.W. 

 and N.N.E. and transverse faults and thrust-fractures in 

 the Alps. 



In my interpretation the Lenzerhorn Chain represents 

 fold-arcs on the south-east of the local basin. The 

 curved strike veers here from north-east to west, and 

 there are also fault-radii in N.N.W. direction. The 

 oblique shearing that has occurred here is apparently 

 stronger than in the Rhatikon, but not nearly so strong 

 as in the Brigels and Vorderrhein Chain, which repre- 

 sents the southern fold-arc in the Glarus district. My 

 inference is that the original Glarus-Prattigau crust-basin 

 with its peripheral folds has been cut into two unequal 

 halves by the development of the Rhine fracture during 

 the later Alpine movements. The Rhatikon and the 

 Glarus have been rent asunder at the north of a radial 

 Alpine fracture. The regional Alpine movements have 

 superinduced wider curves above the local curves and 

 have affected the two halves of the basin with different 

 degrees of intensity, so that the eastern half occupies a 

 broader area from north to south than the more strongly 

 crumpled western half. 



Hence the ground-work of the structure in this region i 



NO. 1630. VOL. 63] 



is based upon intersecting fold-arcs, and all the additional 

 details supplied by Prof. Rothpletz can be adopted in 

 the scheme of Alpine geology which I demonstrated in 

 1899 upon the basis of the "fold-arc" and the "unit- 

 area of depression" surrounded by torsion-curves of 

 strike (Report Intern. Geogr. Congr. Berlin, 1899). 

 The science of geology finds itself, at the threshhold of 

 this new century, entering upon a development of re- 

 search in which advance can only be made if the student 

 of earth-structures can bring to bear upon his observa- 

 tions a sound knowledge of the laws of higher mathe- 

 matics, dynamics and physics. And, if I may make a 

 forecast, it is that structural geology will be ere long 

 grouped in our university curricula with these exact 

 branches of science. 



Maria M. Ogilvie-Gordon. 



THE ZOOLOGICAL RECORD FOR 1899. 

 The Zoological Record. Vol. xxxvi. Being Records of 

 Zoological Literature Relating Chiefly to the year 1899. 

 Edited by D. Sharp. (London : Gurney and Jackson, 

 1900.) Printed for the Zoological Society. 



THE editor of this invaluable record is to be con- 

 gratulated on its early issue, the present volume 

 having been in the hands of the public during the first 

 week in December. The amount of energy on his part 

 necessary, in order to secure punctuality in the delivery 

 of their quota of manuscript from twelve contributors, can 

 scarcely be realised except by those who have undergone 

 a similai* experience. This early appearance of the 

 volume is, however, in part due to the circumstance that 

 the contributors are now instructed not to await the 

 arrival of the whole of the year's literature, but to 

 be content with as much as is to hand at the date 

 when their manuscript is required. That this decision 

 is a wise one there can be no doubt, for it is much 

 more important to issue the record at as early a date 

 as practicable, than it is to insist on its containing 

 the whole available literature of the year to which it is 

 specially devoted. 



This leads naturally to the remark that some want of 

 uniformity is noticeable with regard to the inclusion of 

 portions of certain serials in each year's record. For in- 

 stance, the fourth part of the volume of the Proceedings 

 of the Zoological Society of London for each year is not 

 issued till well on in the following year. Now we find 

 that in the records of mammals and birds, the contents of 

 this part are quoted in the year to which they nominally 

 belong, while they are omitted in the reptile and fish 

 records. It is not for us to discuss which plan is the 

 better, but we do urge that strict uniformity in this 

 respect should be insisted upon by the editor. 



Nor is this the only instance in which that functionary 

 does not appear to have his team sufficiently well in hand. 

 As the record of insects is by the editor himself, we may 

 take this as the model which ought to be strictly followed 

 by all his subordinates. This record is preceded by a 

 carefully written introduction, bringing into special notice 

 the leading features in the year's work ; the papers are 

 numbered, and where a series of new species are de- 

 scribed in any particular genus, they are collectively 

 designated as such at the end of the paragraph. In the 



