Flints of the Upper or White Chalk. 169 



Before passing on from this portion of my subject, I beg 

 leave to say that the tone of Mr. Sollas's remarks, and more 

 particularly of the last-quoted paragraph of his paper, would 

 nave been answered only by one general expression of repro- 

 bation on my part, but for the way in which he has attempted 

 to make the personalities and other matters I complain of serve 

 the purpose of depreciating my opinions, and has thus left me 

 no alternative but to enter fully into the facts. 



Mr. Sollas opened his paper by citing the opinion of 

 Ehrenberg and Sir Charles Lyell (which he says "is sup- 

 ported by Dr. Wallich " and others) that the silica of the flints 

 " has been derived from siliceous organisms, either collected 

 into distinct layers or scattered through some other deposit, 

 like the siliceous remains now found dispersed in the Atlantic 

 ooze." A glance at p. 265 of Sir Charles Lyell's latest work, 

 * The Student's Elements of Geology,' will nevertheless show 

 that such was not the opinion entertained in 1871 by that 

 illustrious geologist. I can answer for myself, moreover, that 

 no opinion of the kind has ever been entertained or expressed 

 by myself, either elsewhere or in my paper on the Chalk 

 flints. Referring to the analogy that has been drawn between 

 the Atlantic mud and the chalk, and the inference which he 

 alleges has been based on this analogy, " that siliceous 

 organisms were at one time present in the chalk, just as they 

 now are in the ooze," Mr. Sollas states that he will at once 

 " proceed to make this inference independent of analogy, by 

 showing that it is really nothing less than a statement of fact" 

 (^c.ciV. p. 438). And this he immediately claims to have 

 done on evidence afforded by the Trimmingham flints, which 

 goes " straight to the point ^^^ but which I venture to affirm 

 leaves the inference as thoroughly dependent on analogy as 

 ever it was — the only change in the situation being that, 

 whereas I and other writers on the subject avowedly drew our 

 analogy from analyses of chalk taken from the middle of a 

 chalk-stratum, he drew his, not, as he pledged himself to do, 

 from the Trimmingham Flints, but from chalk adherent to 

 the crevices of the flint-nodules, and separated from them by 

 washing and subsequent treatment with hydrochloric acid. 

 It is true he does not confine himself in this matter only to 

 the evidence afforded by the Trimmingham flints, but says his 

 conclusions are supported by what he has observed at the 

 Niagara chert-beds, the Carboniferous beds of Scotland and 

 North Wales, and also in other English strata. But at 

 p. 441 he says, in reference to " a difficulty " he has encoun- 

 tered : — " This is to be found in the restriction of the flints to 



