Wood, jun. *, Mr. J. E. Taylor† , Mr. Harmer‡ and Mr. Maw §, the Rev. O. Fisher||, Mr. Ray Lankester¶, and others, have since contributed largely to our knowledge of it. With respect to these papers, many of which (those especially of Mr. Wood and his colleagues) are marked by much research and original opinions, I feel rather at a loss how to proceed. Were I to give the views of each author and discuss the points of difference between us, I fear I should have to lengthen this paper to an extent which might be wearisome to the Society. If I do not therefore always notice all the points wherein I may agree or differ from other observers, I beg they will not consider it arises from oversight, or from want of due estimation of their researches, but from the mere necessity of avoiding the long details which a discussion of the controverted points would entail. I may be further justified in this course by the circumstance that my own researches are in great part anterior to most of the papers in question. It may be observed that where the several conclusions arrived at thus independently prove to be concordant, they must be entitled to greater weight. One object of this paper is also to give more fully than has been hitherto done the stratigraphical details of the several pits and particular coast- sections in which the relation of the several beds can be determined, following their range from the Red-Crag district and proceeding northwards through the Norwich-Crag district.
I described the Chillesford beds in 1849 ; and I then expressed an opinion that they were probably of the age of the Mammaliferous Crag of Norfolk, or possibly one degree more recent, an opinion shared by Mr. Searles Wood after an examination of the fossils **. My own observations, continued since that period, and the active researches of many of the geologists just named, have confirmed that suggestion. It has further been shown that the Norwich Crag may be divided into an upper and lower division, the former corresponding with the Chillesford Sands and possessing a deeper-water fauna of a more northern character than the other,— conclusions which I accept with, possibly, a few modifications. Another interesting question raised by Mr. S. Wood, jun., and his colleagues relates to the position of the Weybourne Crag ; and on this we do not altogether agree.
In my last paper it was shown : — that the Chillesford Clay was probably the upper and deeper-sea portion of the second or higher
- " On the Red and Fluvio-marine Crags " &c., Ann. & Mag. Nat. Hist. March
1864 ; ' On the Upper Tertiaries of the Eastern Counties,' 1865 ; Geol. Mag. vol. v. p. 452; Quart. Journ. Geol. Soc. vol. xxii. p. 546.
† Geol. Mag. vol. iii. p. 273, vol. iv. p. 331, and vol. vi. p. 231.
‡ Ibid. vol. vi. p. 231.
§ Ibid. vol. iv. p. 560.
|| "On the Relation of the Norwich Crag to the Chillesford Clay," Quart, Journ. Geol. Soc. vol. xxxii. p. 19.
¶ Quart. Journ. Geol. Soc. vol. xxi. p. 221 ; and Geol. Mag. vol. iv. p. 91. vol. v. p. 254, and vol. vi. p. 47.
- Instead, however, of their overlying both the Red and Coralline Crag unconformably, I afterwards found that, while they were unconformable to the
latter, they succeeded to and passed transgressively off the former.
