Hevieivs — Symonds' Records of the Hocks, 85 



and meaning of the " Silurian cHef," and is a fit exponent of his 

 views and country. 



The table at the commencement of the chapter devoted to Silurian 

 geology comprises the author's accepted system, his lowest formation, 

 being the " Lower Llandeilo " ; thus throwing the Tremadoc and 

 Lingula flags of the Geological Survey and Sir Roderick Murchison 

 into the Upper Cambrian. Sir Eoderick in his last edition of 

 Siluria included all below the Llandeilo series in his "Primordial 

 Silurian," not allowing the term Cambrian as then understood. It 

 must be admitted that even now there is extreme confusion as to 

 the subdivision of the stratified series below the Lingula flags. 



The Menevian, Harlech, Longmynd, St. David's, etc., etc., rocks 

 have yet to be satisfactorily correlated* The Menevian beds are 

 placed by Mr. Symonds as a passage group between the Lower 

 Lingula flags and the Harlech grits. The vast accumulation of both 

 eruptive and contemporaneous lava flows, as well as volcanic ash 

 deposits, define in a most marked manner the commencement of 

 the Lower Llandeilo, or close of the Lingula flag period. These 

 phenomena are grandly shown in the great ranges of the Cader, the 

 Arans, and the Arenigs, etc., in Wales, and the Skiddaw area in 

 "Westmoreland, etc., where they are also extensively interbedded or 

 inter stratified with the slates and grits of that classical area* The 

 author's description of the scenery^ history, and antiquities of the 

 country occupied by the Lower Silurian rocks, a^s well as the 

 incidental notices upon the occurrence and distribution of rare forms 

 in the flora and fauna, must be read to be appreciated. They show 

 a rare appreciation of the true and the beautiful in nature. The 

 singular ridge of rocks termed " Stiper stones " by Murchison in 

 his first and great Silurian system are well described, and should 

 be made the special object of a journey of inspection over the wild 

 tract of the Longmynd Mountain. These grey and buff sandstones 

 belong to the Lower Llandeilo period. Annelide tracks and burrows, 

 vertical to the plane of bedding, riddle these ancient sandstones, 

 Arenicolites linearis being the architect of their once submarine per- 

 forations and burrows. The author recommends the student who 

 wishes to master the intricate geology of the Longmynd area to 

 spend some time at Church Stretton, Bishop's Castle, etc. We have 

 done so, with pleasure and profit. This once Cambrian island in the 

 Silurian seas is even now, geologically and physically speaking, a 

 terrestrial one, surrounded, as the Longmynd is, by unconformable 

 rocks of Upper and Lower Silurian age at every point of the compass. 

 The author's description of the Caradoc and Bala rocks over the Snow- 

 donian, Caradoc, and Cader Idris districts, the Berwyns, the Wrekin, 

 etc., reads more like some fairy tale. Every page is full of exact 

 instruction, without that severe style characteristic of ordinary manuals 

 upon geology. Chapter v. treats of the Middle Silurian rocks, a 

 division not admitted by Sir Eoderick Murchison or the Geological 

 Survey. The author, too, has incorporated and placed the Lower 

 Llandovery rocks at the base of his triple division of the Middle 

 Silurian, the Tarannon shales being the uppermost member. We are 



