10 genera 



and 



12 species. 



22 „ 





44 ,, 



13 „ 





22 „ 



none. 





none. 



10 „ 





27 „ 



54 „ 





211 „ 



34 „ 





128 „ 



33 





168 „ 



568 Revieics — R. Etheridge's Manual of Geology. 



extensively Mr. Etheridge has dealt with this most important subject 

 before attacking the palgeontology in detail. 



According to the census given on p. 276, the Plants of the British. 

 Carboniferous rocks number 75 genera and 328 species, their 

 stratigraphical distribution through the following eight series or 

 groups of strata being as follows : — 



Calciferous Sandstone 



Lower Limestone Shale 

 Carboniferous Limestone ... 



Toredale Eocks 



Millstone Grit 



Lower Coal-measures 



Middle 



Upper 



Ten genera are largely represented in Britain, and contain 192 

 species out of the known 328 ; they are Alethopteris 10 species, 

 Asterophyllites 12, Calamites 12, Lepidodendron 22, Lepidostrohus 8 

 (probably we may never know to what species of Zepidodendra all 

 these Lepidostrobi belong), JVeuropteris 23, Fecopteris 29, Sigillaria 31, 

 Sphenopteris 34, Ulodendron 11. 



With regard to the Actinozoa, he says that 9 families, 39 genera, 

 and 145 species constitute the Carboniferous Ccelenterate fauna, 

 the most prolific families being the Favositidas and Cyathophyllidse. 

 No species of Coral is known above the Yoredale rocks, and only 

 2 species occur in that series, viz. Favosites tumidus and Zaplirentis 

 Phillipsii. The Carboniferous Limestone contains nearly all the 

 species in the list, and evidence may be obtained of extensive reefs 

 composed mainly of Lithostrotion, Lonsdahia, and forms of CyatTio- 

 phyllum. Of the Carboniferous Poltzoa he further says that "as a 

 group (they) constitute by far the largest series in any division of 

 the Paleozoic rocks." Seventy-eight species range through the 

 three lower horizons, i.e. through the Carboniferous Limestone, the 

 Lower Limestone Shales, and the Calciferous Sandstone, the whole 

 group essentially belonging to the calcareous rocks and shales. 

 Ceriopora, Fenestella, Glaiiconome, and Pohjpora are the most prolific 

 genera. The author is not quite correct in stating that not a single 

 species of Polyzoa occurs in the Millstone Grit ; since a species of 

 Fenestella is by no means uncommon in the " Cayton Gill Beds," 

 though possibly it may not have been named as yet. Nevertheless 

 we rather think that it is quoted in one of Mr. Fox Strangway's 

 Geological Survey Memoirs, Moreover we believe that where the 

 limestones are thick in the Yoredale rocks, possibly moi-e than two 

 species of Corals might be obtained. 



Two chapters are devoted to the "Permian orDyas Strata," which 

 the author regards as probably o^ freshwater origin. From a paragraph 

 on page 307 we arrive at this interpretation of freshwater : — 

 " The water in these basins must have undergone extreme concen- 

 tration, and chemical precipitation, so as to have resulted in the 

 accumulation now presented of dolomites, saliferous clays, rock salt, 

 gypsum, and anhydrite." Apart from this slip, we should demur to 

 the statement that much of the Mai^nesian Limestone of the North 



