AND STRUCTURE OF THE BELEMNITE. 399 



but, in place of this, the highest range is the first that would 

 arrest the loaded siliceous solution, and that formed, the flints 

 being often so closely deposited, as even to become continuous, 

 the connection must have been interrupted, and many of the 

 lower cavities left vacant, — a circumstance unknown in the his- 

 tory of chalk-rocks. It may be remarked, however, that Mr 

 Parkinson's observations are meant to apply to the foi'mation 

 of pebbles as well as flints ; but the formation of agate and 

 calcedony lead to a totally diflferent inquiry. 



The essay read by Dr Hutton on the 7th of March, and 

 4th of April 1785, on the Theory of the Earth, published in 

 the Transactions of this Society, is well known to embrace, in 

 all its plenitude, the igneous theory of that philosopher ; and 

 in it we find the opinion which he entertained respecting the 

 formation of flint to be as follows. " Tlie actual form in which 

 those flinty masses are found, demonstrates, 1st, That they 

 have been introduced among those strata in a fluid state, by 

 injection from some other place. 2d, That they have been 

 dispersed in a variety of ways among these strata, then deeply 

 immersed at the bottom of the sea. And, lastly, That they have 

 been there congealed from the state of fusion, and have re- 

 mained in that situation, while those strata have been removed 

 from the bottom of the ocean to the surface of the present 

 land." Trans, vol. L p. 232. 



The elegant commentator of Dr Hutton only seeks in the for- 

 mation of flint for an illustration of the igneous origin of that 

 substance. He observes, § 20. " The round nodules of flint that 

 are found in chalk quite insulated, and separate from one ano- 

 ther, afford an argument of the same kind (alluding to fluidity 

 produced by fusion), since the flinty matter, if it had been car- 

 ried into the chalk by any solvent, must have been deposited 

 with a certain degree of uniformity, and would not now appear 

 VOL. IX. p. II. 3 E collected 



