ON MESSRS. BAKER AND TATE's NEW FLORA. 357 



Fig. 5. View of underside of central tooth : a, cutting-margin ; b, central 

 area or facet, exhibiting transverse gi'ooves ; c c, lateral facets ; 

 d, root. 



Fig. 6. Shagreen, tubercles much enlarged, in their natural order. 



Fig. 7. Three stellate tubercles of the same. 



Fig. 8. Two smooth tubercles. 



PLATE XI. 



Fig. 1. A group of teeth, a little over the natm-al size, of Janassa hitumi- 

 nosa, seen in front, the anterior cutting-margins being exposed : 

 a, central row of teeth of upper jaw; 5, of under jaw, with 

 their sides exposed ; c, petalodontoid teeth ; d, shagreen. 



Fig. 2. Another group : a, the upper surface of two teeth of the upper 

 jaw ; 5, the remains of teeth of the under jaw, with their under 

 surfaces exposed; c, scattered petalodontoid teeth, with their 

 undersides uppermost. 



XIX. — Note on the " Geology '' of Messrs. Baker and Tate's New 

 Flora of Nortlmmherland and Durham. By Jas. W. Kirkby. 



In the first chapter (geology) of the "New Flora of Northum- 

 berland and Durham," there are certain statements which I 

 wish to notice. These statements relate to the Permian forma- 

 tion, as described at pp. 18-21. 



In commencing the description of the formation the author — 

 Mr. George Tate — says that only one member of it appears in 

 the two counties named, though "it xoas usual to group with it 

 an irregular, loose, sandy deposit, and some red sandstones lying 

 beneath it." From the way this is put it might be supposed that 

 the classification of these rocks in the Permian series was a thing 

 of the past, and that geologists generally agreed in placing them 

 with the Carboniferous system. But this ought scarcely to be 

 said when perhaps the author and Mr. Howse are the only two 

 who adopt that view of the question ; while by Sir Roderick I, 

 Murchison,* Sir Charles Lyell,i- Professor Eamsay,| Professor 



* Siluria, 4th edit, rp. 327, 8, 9. t Elements of Geology, 4th edit., pp. 301 & 305. 

 X Geological Map of England and Wales, 3rd edit. 



