Beviews — M. Reehs — Crydal Draiiing. %% 



first. From this the author concludes that towards the close of the 

 Carboniferous period a platform of highly convoluted Highland 

 schists lay buried beneath a thick mantle of Old Red Sandstone and 

 Carboniferous rocks, which rested upon the schists with a gentle slope 

 to the south-east. The contorted Lower Palaeozoic rocks of the 

 Southern Uplands were hidden under a similar cover, whilst gently 

 folded Upper Palaeozoic rocks were faulted down between the Highland 

 and Southern Upland boundary faults. The plane had a slope to the 

 south-east which gave the initial direction to the primitive rivers. 

 These rivers cut down into the schists beneath, and carved out the 

 transverse valleys of the Southera Highlands, whilst the longitudinal 

 valleys were formed by tributary streams eroding courses in the belts 

 of softer rock. The initiation of the river-system is thus thrown back 

 into late Pala30zoic times, but further on the author uses the old 

 argument from the disposition of the Tertiary dykes that the erosion 

 of the Highland glens has been accomplished since Miocene times. 

 What, then, was happening between late Carboniferous and the end 

 of Miocene times ? There is only the cutting through of the cover 

 of Carboniferous and Old Red Sandstone rocks to fill up this vast 

 interval. It would be much more plausible to assume that the river- 

 system was initiated on a former cover of Mesozoic rocks. The origin 

 asciibed to the longitudinal section of the Tay between Ballinluig 

 and the head of Glen Dochart will probably give most readers the 

 impression that this portion of the river originated as a strike stream 

 of its present length, and merely cut down through the cover of 

 Upper Palaeozoic rocks and the weak schists of the Grarnetiferous Schist 

 zone, whereas an inspection of a good map shows that it must have 

 cut back from the trunk stream and captured the head-waters of 

 several transverse streams. The whole treatment of river development 

 leaves much to be desired. The many interesting problems which 

 this district offers for solution are barely indicated. Although the 

 path of the Tay is followed in detail, the relation of this river to its 

 tributary streams and to neighbouring river-systems is not touched 

 upon. The other rivers are treated very briefly. 



The author then proceeds to a long description of the ruggedness or 

 smoothness of the hill-slopes in the various schist ' zones', and notes 

 the scarped features of the Ochil and Sidlaw Hills. Defiles are 

 mentioned as intersecting the former chain, but no explanation of 

 them is offered. Except to claim the lake basins as the work of the 

 ice-sheet, the influence of the glaciers of the Ice Age on the river- 

 systems receives no con.sideration. 



The work concludes with a shoi't bibliography and an index. The 

 text has been carefully corrected in the press and is practically free 

 from typographical error. The label "Upper O.R.S." in fig. 10, 

 vol. ii, is misplaced. 



V. — Hints Fou Crystal Drawing. By Margaret Reeks. Longmans, 



Green, «& Co. 3s. %d. 

 n^HIS little book will prove a very welcome addition to the sources 

 _L of information available to those beginning the study of 

 crystallography. It is intended to show the student how to make 



