564 Reviews — R. Ethevidge's Manual of Oeology. 



If the so-called Upper Gneiss is to be regarded as the result of the 

 rolling out of Archsean rocks in Palaeozoic times, with the production 

 of abundant crystalline change, and in some cases even with an incor- 

 poration of Palceozoic strata, it becomes almost a point of casuistry 

 to what period these great mountain masses should be assigned. 



In the earliest chapters the author devotes a few pages to the 

 beginning of things, though of actual Cosmogony there is none. He 

 still seems to regard " Eozoon " as a gigantic Foraminifer, which 

 flourished in the earlier seas under a temperature a little below boil- 

 ing point. After comparatively brief allusions to Archasan topics, he 

 fairly settles down to his work (Chapter IV.), and with the help of 

 Dr. Hicks gives us the base of the Palaeozoic column as it appears in 

 England. 



Part I. of this volume, with the exception of the introductory 

 matter previously noted, is devoted to the Lower Paleozoic Eocks 

 (Chapters IV. — XVII. inclusive), and maybe regarded as containing 

 a most exhaustive summary of the several faunas hitherto discovered 

 in the British area. It might perhaps be going too far to say that the 

 arrangement in all cases is not open to criticism. The author seems 

 to have had such a press of matter, that he has been somewhat 

 puzzled where and how to place it, and his difficulty has been further 

 increased by the conflicting nomenclature of the system itself and 

 its primary divisions. 



The Harlech or Longmynds, the Menevians, the Lingula Flags, 

 and the Tremadoc rocks constitute the first or lowest section. This 

 section corresponds to a certain extent with the first or primordial 

 fauna of Barrande. Most of the great groups of Invertebrates here 

 enter an appearance for the first time. This fauna is rich in Trilo- 

 bites, especially of the genera Agnostus, Paradoxides, Niobe, etc. As 

 an example of the author's method of handling a particular series we 

 append an abridgment of the " Palaeontology of the Lower Tremadoc 

 Eocks " (p. 54) : — 



" Hydkozoa. — The Shineton Tremadoc rocks have yielded two 

 species, Clonograptus and Bryograptus Callavei, of Lapworth, both 

 belonging to the family DichograptidEe. These are the oldest RJiabdo- 

 pliora known. 



" AcTiNOZOA. — None known below the Llandeilo rocks. 

 " EcHiNODEEMATA. — Dendrocfhius cambrensis, Hicks, and PaJce- 

 asterina Bamseyensis, Hicks, are both from the Lower Tremadoc beds 

 of Eamsey Island, St. Davids ; they are the first known species of the 

 orders Crinoidea and Asteroidea. 



" Crustacea. — Only two new genera appear with the coming-in 

 of the Lower Tremadoc • . . ; but the whole Crustacean fauna 

 comprises 13 genera and 24 species, of which 10 genera and 19 

 species especially characterize the Lower Tremadoc. They are so 

 essential to a right understanding of the Lower Tremadoc rocks, and 

 so distinct from the fossils of the Upper Lingula Flags, that we 

 enumeiate them The Lower and Upper Tremadoc are con- 

 nected only by Agnostiis princeps, Ampyx prcemmtius, and Ogygia 

 scutatrix. 



