T^OTES AI^D QUEEIES. 



39 



instance, with the exception of the Northamptonshire beds, which have 

 been carefully noted by my friend, the Eev. A. N. Griesbach, I have 

 visited the localities given in this work," but in no part of that mono- 

 graph has my friend referred the Northampton Sands to the lias. Mr. 

 Macalister has been therefore altogether misinformed on this subject. 

 I submit that it ought to be a rule with gentlemen furnishing papers to 

 the valuable pages of the ' Geologist,' in every case to refer to the original 

 articles from which they quote. Yours most truly, 



Thomas Weight. 



Cheltenham, November, 1861. 



NOTES AND QUEEIES. 



Subdivisions of the Chalk Eoemation. — The generally accepted 

 subdivisions of the chalk are, — 1, Upper White Chalk with bands of Flint 

 nodules; 2, Middle or Lower White Chalk; 3, Grey Chalk or Chalk 

 Marl. 



These have been in undisputed use for very many years, not because they 

 do not require any modification to render the accordance more definite and 

 more rigidly corresponding to the accumulation of information which has 

 been going on since their introduction, but chiefly because chalk, — at least 

 English chalk, — is white or of a pale grey, which when the beds are in a 

 dry state is so nearly white, that ordinary eyes do not see the difference, 

 and ordinary collectors do not care about it so long as they can get hold of 

 a fine fossil. 



Still, however, it is very necessary, and high time that some one should 

 take in hand to define accurately the lines of division, especially that be- 

 tween the upper and lower white chalks. 



I doubt very much that the cessation of the bands of flints denotes the 

 demarcation between the upper and lower white chalk (middle chalk of 

 some authors) : they should be properly, and must be ultimately, separated 

 by a characteristic difference in the distinguishing organic remains. 



With the lowermost bands of flints (Plate II. a) very numerous beds of 

 ventriculites and sponges set in, and are continued far below the termina- 

 tion of the layers of flints, down to a very thick bed of pure white 'chalk 

 {h), that rests upon a very marked and peculiar stratum about two feet 

 thick (c), which, from the v^ eathering out of its upper and under surfaces, 

 forms a marked line as far as the eye can see the distinctions of bedding 

 all along the coast. 



This bed, in my own note-books and in conversation, I have familiarly 

 termed the " two-foot stratum." 



Below this we have again a thick bed of white chalk, free from flints. At 

 least, such is the order in the section to M^hich these remarks more particu- 

 larly refer, namely, that presented by the East or Castle Clifi" at Dover, 

 of -which we give a view in Plate II. 



This "two-foot stratum " is persistent throughout Kent, and I have met 

 with it both in Surrey and Sussex, and it will therefore probably form one 

 of the best and most unmistakable guides in inland quarries to those 

 particular beds of white chalk to which we wish to draw attention, for the 

 purpose of getting all the information we can as to their geographical area, 

 order of succession, and organic contents in other chalk districts, so that 

 the true horizon of division, as formed by distinctiveness of organic remains, 

 may be properly made out. 



