54 DESCRIPTION OF THE STRATA. 



with ferniginous spots, which are larger or smaller, according to tl>e 

 quantity of the matter imbedded. 



But the substance . which occurs most plentifully in the white 

 chalk is jiint. This is well known to be the constant associate 

 of the white chalk; and it has long been, and still is, a matter of dis- 

 pute, how substances so different in their qualities have become so 

 nearly related. Without agitating that question, at least for the pre- 

 sent, we shall merely state the actual connection between the chalk 

 and the flint, as it appears in our district. 



Some have described the flint as interstratified with the chalk, 

 stating that thin strata of flint are found alternating with thick strata 

 of chalk; but on a minute examination of the chalk rocks, particularly 

 at Flamborough Head, where they are most open to inspection, we 

 can assure our readers, that the flint is not interstratified with the 

 chalk, in the ordinary acceptation of that word, but merely imbedded 

 ii^ it. Sometimes it occurs in irregular tubercular nodules, and some- 

 times in flat pieces, like thin cakes : and as a number of these flat 

 plates are often found nearly in contact with one another, or actually 

 adhering or running into each other, on the same level or floor; when 

 several of these lines of plates are seen rising one above another, as is 

 sometimes the case, they present the appearance of alternate strata ; 

 especially as they usually run parallel to one another, and to the 

 general bed. But if we follow any one of those seams, we soon find 

 it to run out ; and in searching for its continuation further on, instead 

 of meeting with a seam or line of plates on the same floor, we may 

 expect to find others a little higher or a little lower ; or perhaps we 

 may find a fresh seam commencing above or below it before its termi- 

 nation. This is something very different from an alternation of strata; 

 especially as the seams are not continuous, except for very short dis- 

 tances ; and the intervals between the pieces of flint are all filled up 

 with the chalk, in the same manner as the intervals in rows of nodules 

 ill some of our schistose strata, are filled up with schistus. 



