400 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [April 5, 



gical Survey Memoir' on Sheet 46. I have traced it from near 

 Henton (in Sheet 7 of the Geological Survey Map) on the south- 

 west to near Ravenshorough Castle (in Sheet 46, N.E.) on the north- 

 east, along which course there is no lack of sections. I believe that 

 it occurs further to the south-west, for in passing by train through the 

 long cutting in the bottom part of the Chalk on the Great Western 

 Railway north of "Wallingford Road Station, I noticed a constant 

 hard bed ; and I should think that it will be found still further 

 westward, near the foot of the Chalk range. 



(e). A rather marly white chalk without flints, which breaks up 

 into large irregular- shaped blocks with more or less curved surfaces, 

 comes on above the Totternhoe stone, and is in turn overlain by : — 



[d). Hard bedded white chalk without flints, partly yellowish and 

 of a nodular structure, with thin soft grey marly layers. This 

 causes a slight rise of the ground at the foot of the great ridge. I 

 have also seen this hard chalk to the north-east, in Hertfordshire 

 and Bedfordshire. 



(c) . The thick mass of the white chalk without flints, but with 

 thin layers of soft grey shaly marl here and there, which mark the 

 bedding. There are sometimes a few flints in the top part of this 

 division, which forms the flank of the great escarpment. 



(b). The hard and more or less nodular " Chalk-rock," often 

 fossiliferous. Of this no further remarks are needed here, as I 

 have described it to the Society before*, and have elsewhere noted 

 most of the sections in Buckinghamshire f, 



(a). The white chalk with flints, of which the lowermost part 

 only occurs at the top of the escarpment, whilst the higher beds 

 come on in succession over the table-land southwards, the thickness 

 of the whole being possibly 300 feet. 



4. On the Chalk of the Isle oe Wight. 

 By William Whitakee, B.A., F.G.S. 

 The following notes were made during holiday rambles in the au- 

 tumn of the years 1863 and 1864, and as some of them seem to throw 

 a little light on a formation the details of which have been hitherto 

 somewhat neglected, I trust that they may be not unacceptable to 

 the Society. 



The divisions of the Chalk in the Isle of Wight are well enough 

 known, but nevertheless it will be as weU to mention them here 

 before giving the details as to the line of demarcation between the 

 first two, which is the special object of this paper. They are — 



White Chalk with flints, many hundred feet thick (1200 feet 



or more ?). 

 White Chalk without flints, about 200 feet ? 

 Chalk-marl, 60 or 80 feet ? 

 The " Chloritic Marl," which my friend and colleague, Mr. Bris- 

 tow, classes as the bottom part of the Chalk J, I should rather look 

 * Quart. Journ. Geol. Soc. vol. xvii. p. 166. 



t Geological Survey Memoir on Sheet 7, pp. 5-7, where the range of the 

 Upper and Lower Chalk is also given. + Ibid. Sheet 10, p. 25. 



