The Building of the British Ides. 317 



increased weight now attached to the evidence of the petrology 

 of the sedimentary rocks. The importance of palaeontology in the 

 interpretation of physical geology has relatively declined. The 

 stratigraphical correlation, on which the whole discussion rests, 

 is no doubt ultimately dependent on the evidence of the fossils ; 

 but the lithological evidence is recognized as of increasing value and 

 reliability. It is therefore natural to find that Mr. Jukes-Browne 

 makes frequent reference to the luminous suggestions of the late 

 J. G. Goodchild, a pioneer in this field of inquiry. A large share 

 of space is given to such formations as the Trias, regarding which 

 the lithological evidence is the most instructive. Mr. Jukes-Browne 

 accepts the general conclusions as to the origin of the English Trias 

 of Professor Bonney, who, he remarks (p. 233), " has given so much 

 time and attention to a study of the Bunter deposits, and has such 

 an intimate knowledge of the rocks concerned in the question, that 

 no on.e is more likely to have arrived at correct conclusions on the 

 subject." 



The book consists of a brief introduction on general principles and 

 of fifteen chapters, most of which deal with one geological period 

 each. These chapters usually consist of a concise statement of the 

 stratigraphical evidence, and a discussion of its indications as to 

 the physical geography of each period. The results are illustrated 

 by a sketch-map and sections. 



It is impossible to refer to all the interesting, noA'el, and 

 controversial questions with which the book deals, for it ranges 

 from the genesis of Archean gneisses to that of Boulder-clay ; it 

 considers how far the distribution of living Badiolaria gives reliable 

 guidance of bathymetric conditions in Palaeozoic times, and it has 

 to deal with scraps of tectonic evidence which are capable of 

 alternative or perhaps of several explanations. The sections on 

 the Scottish pre-Cambrian and Cambrian rocks are the least 

 satisfactory in the book ; the chapter on the former shows the 

 increasing weight attached to the formation of gneisses by 

 absorption rather than by pressure alone. The author calls 

 attention to the increase in the known range of the British 

 Cambrians by their identification from bores in Suffolk ; but the 

 announcement of Mr. Campbell's discovery of Cambrian near Stone- 

 haven, and the restoration of the Durness Limestones to the 

 Ordovician, which involves a radical change in British Cambrian 

 geography, came too late for insertion. 



In the account of the Devonian System the author makes a useful 

 protest against the too frequent description of coral-bearing lime- 

 stones as coral reefs. He points out that some of the Devonian 

 limestones thus described are crinoid limestones, and their 

 identification as coral reefs can only be regarded as a mistake. 

 He, however, appears to doubt whether any British Palaeozoic lime- 

 stones should be called coral reefs. Prom my recollections of some 

 Devonian Stromatoporoid limestones, 1 have never hitherto hesitated 

 to affirm the existence of coral reefs in English Devonian seas. The 

 author quotes Goodchild's refusal to accept any of the coralliferous 

 limestones in the Carboniferous beds to the south of the Lake District 



