S76 



Dr. Boase's Inquiry into the Nature 



References. 



Localities. 



Names. 

 Pisces. 

 Diodon, very gibbous and sulcated palatal teeth, from Sahaih. 

 Palatal teeth resembling those of Squalus Perlon*, from Swaffham. 



("Geol. S.E.England, \ 

 \ p. 132. f. 5. / 



Ibid. figs. 3. 4. 

 Geol.Suss.,t.32.f.l2,14. 

 Ibid. t. 32. f. 22. 



Squalus Zygaena, teeth 



Mustelus, teeth 

 galeusf, teeth 

 PhillipsiiJ,teeth 

 a vertebra 



fSwaffham, Litcham, 

 < Docking, and Thet- 

 L ford. 



Swaffham, Thetford. 

 Ditto, Saham. 

 Ditto. 

 Do., Litcham, Lexham. 

 Ditto. 



Ditto, Saham. 

 Ditto, ditto. 



Zeus Lewesiensis § Ibid. t. 35. f. 1. 



Esox Lewesiensis Ibid. t. 41. f. 1 



Scales, very imperfect. 



The usual series of tertiary beds overlying the chalk is 

 not met with in Western Norfolk. 



[To be continued.] 



XLVIII. An Inquiry into the Nature of the Structure of 



Rocks. By Henry S. Boase, M.D. 9 #c.f 

 TN the Transactions of the Geological Society, (Second Series, 

 * vol. ill- part 3.) just published, there is a paper from the pen 

 of Professor Sedgwick, " On the Structure of large Mineral 

 Masses**," in which opinions are advanced very different from 

 those advocated in my " Treatise on Primary Geology." 



I have therefore been induced to enter once more on this 

 subject, in the hope of originating a discussion which may ul- 

 timately tend to reconcile, if possible, those points on which 

 we disagree. And it fortunately happens, that of all geolo- 

 gical speculations there is none, perhaps, more tangible than 

 that concerning the nature of the structure of rocks; none 

 which can be more readily submitted to the test of facts ; and 

 none, therefore, from which we may expect to derive more 

 satisfactory results. 



The Professor, in the very first sentence of his paper, states 

 that " all solid mineral masses must have undergone some 

 change since the time of their first production." If it be in- 

 tended only to imply by this, that all mineral masses are not 

 now in the same state as when their incoherent materials were 

 originally deposited, then every one must admit the correct- 

 ness of this assertion ; but if, on the other hand, this state- 



• Geol. S.E. of England, p. 132. fig. 7. 



f Resembling those of Sq. Cuvieri. 



X Species unknown, Geol. S.E. England, p. 132, f. 6. 



§ Part of a spine; the vertebrae very tender. 



f Read before the Royal Geological Society of Cornwall; and commu- 

 nicated by the Author. 



** [An Abstract of Prof. Sedgwick's paper here referred to, was given in 

 our last number, p. 320.— Edit.] 



