232 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [Feb. 8> 



EXPLANATION OF PLATES X. & XI. 



Plate X. 



Fig. 1. Fragment of the tusk of Trichecodon Huxleyi; terminal portion, showing 

 the fluting of the dentine. From the Red Crag of Suffolk. One-third 

 the natural size. 



2. A flatter specimen of the same, with point complete, and the surface of 



cement preserved. One-third the natural size. 



3. Basal portion of the same, with the cement preserved. One-third the 



natural size. 

 [These three specimens are in the cabinet of W. Whincop, Esq., of 

 Woodbridge.] 



4. Section of a portion of the tusk of Trichecus rosmarus, showing the 



microscopic structure of the three layers. Drawn from specimens 



prepared for the author. 

 6. Section of a portion of the tusk of Trichecodon Huxleyi. Drawn from 



specimens prepared for the author. 

 6. Transverse section of the specimen drawn in fig. 1, showing the "core" 



of granular " osseo-dentine." Natural size. 



Plate XI. 



Fig. 1. Restoration of the tusk of Trichecodon Huxleyi. 



2. Tusk of Trichecus rosmarus. 



3. Tooth of a large Ziphioid Cetacean, probably one of the Belemnoziphii 



{Balmnodon physaloides of Owen), from the Eed Crag, Felixstow; in 

 the author's cabinet. Three-fourths the natural size. 



4. Tooth of Bqualodon, Van Beneden & Gervais ; from the Red Crag, 



Suffolk. In the Woodwardian Museum, Cambridge. 



5. Balcenodon physaloides ; from Owen^ ' British Fossil Mammalia,' p. 536. 

 6 & 7. Teeth of Squalodon, more or less worn, sometimes attributed to the 



Balcenodon of Owen. 



2. Note on the Geology of Hakeogate. By John Phillips, M.A. 

 Oxon., LL.D. Dublin, F.R.S., F.G.S., Professor of Geology in the 

 University of Oxford. 



During naore than forty years the uncommon arrangement of the 

 strata about Harrogate has attracted my attention, and I have 

 made frequent examinations of the surrounding country to learn the 

 peculiarities^of structure of the Upper Palaeozoic rocks which are 

 there exposed. Of late years the information furnished by many 

 quarries has been increased by the cuttings on the North-Eastern 

 Eailway, and thus not only the ranges of Millstone-grit, calcareous 

 roadstone, and Yoredale shales have been settled, but some light has 

 been thrown on the relation of the Permian grits to those of the 

 older series, which was formerly doubtful. The mineral springs are 

 also much more surely referable to a deep source along an axis of 

 movement than was possible when, now almost thirty years since, 

 I pubhshed my map of the north-western tract of Yorkshire*. 



Founded on a mass of particular notices, I propose now to oifer 

 to the Society a few results relating to this district, such as it may 

 be well to consider before the closer scrutiny of the Geological Survey 



* Illustrations of the Geology of Yorkshu-e, vol. ii. 1836. 



