88 Reviews — Dr.Rlcketts — Oii Valleys, Deltas, etc, 



flora, and history, like other descriptive portions of his inter- 

 esting vohime, cannot receive justice at our hands for want of space 

 for quotations ; and to those who know as we do the county described, 

 there is an inexpressible charm in thus mentally revisiting districts 

 that recall days spent amidst scenes so wild, and studies so absorbing, 

 here so truthfullj'- rendered. The Wynd Cliff, Tintern, the bone- 

 caves of the Dowards, Eaven's Cliff, and other classical localities on 

 the Wye, rendered still more so by the varied knowledge imparted 

 to them by Mr. Symonds, close the chapter upon the Carboniferous 

 Limestone. The Coal-measures receive a separate notice, many of 

 the Coal-fields being briefly described. He who would wish to 

 understand the physical geology of the Coal-measures need only 

 visit the great Coal-field of South Wales, where along its northern 

 escarpment, deep central valleys, or southern outcroj)s, all the 

 grand features of this great epoch in the history of the British 

 Island can be read and studied as in no other area in Europe. 



No record of, or memoir upon the Palseozic Eocks, would be 

 complete without some notice of the Permian series which closes 

 the history of Palaeozoic time. It is enough to say that this 

 chapter, like most others in the " Eecords," is interestingly and well 

 done. The book is admirably illustrated, 30 woodcuts are given, 

 illustrating both physical structure and picturesque scenes. The 

 accomplished President of the Cotteswold Club, Sir W. V. Guise, 

 Bart., P.L.S., has enriched the " Eecords " with four exquisite 

 delineations of the "Eligug Stacks" near Pembroke, "Marloes Bay," 

 " The Home of jDraha aizoides," and " St. Gowan's Chapel, Pem- 

 brokeshire." There are also five plates of typical fossils admirably 

 and characteristically drawn by Miss Dora Baker, of Hasfield Court, 

 Gloucestershire. Few of the Sections are original ; Professor Eam- 

 say's North Wales and Sir Eoderick Murchison's Siluria affording 

 the chief. We hope to see in the next edition a geologically coloured 

 map of Wales, adapted to the text. The volume is the basis of the 

 best and most interesting scientific guide ("Eecord") ever yet exe- 

 cuted to elucidate the intricacies, and causes, and effects of Silurian, 

 Devonian, and Carboniferous topographical geology. E. E. 



II. — Yallets, Deltas, Bats, and Estuakies. 

 • By Charles Ricketts, M.D., F.G.S. 

 [Presidential Address to the Liverpool Geological Society, 1872.] 



REEEEEING at first to the subject of Denudation, and to some of 

 the current opinions thereon. Dr. Eicketts observes that although 

 we see the effects of marine denudation most prominently brought 

 before us, yet atmospheric agencies, rain and rivers, have a far larger 

 basis of operation, and wear away much more of our land than the sea ; 

 and that although the majority of our geological formations have 

 been deposited beneath the sea, the sediment must not be attributed 

 so much to the erosion of coast-line as to the transporting power of 

 rivers. Treating of the Palaeozoic rocks, he remarks that, in look- 

 ing at a section, whilst many of these formations have commenced 



