16 F. A. Bedivell — Ammonites in Thanet Cliffs. 



Edw. and H., but it presents . some peculiarities whicTi render its 

 reference to Alveolites not altogether certain. It is distinguished 

 by the remote fissure-like calices with nearly parallel walls, and 



Fig. 3. — A fragment of the upper surface of Alveolites Selwynii, Nich., magnified. 

 From the Corniferous Limestone. 



by the absence of any distinct concentric arrangement of the coral- 

 lites. In the shape of the calices, it somewhat resembles Coenites 

 labrosus, Edw. and H. ; but it is in reality very different, both in its 

 general form and its real structure. 



I have only seen a single example of the species. It is dedicated 

 to Alfred E. C. Selwyn, Esq., F.G.S., the Director of the Geological 

 Survey of Canada. 



Locality and Formation. — Corniferous Limestone, Port Colborne. 

 {To be continued in our next number.) 



VI. — The Isle of Thanet. The Ammonite Zone, the Depth of 

 THE Chalk in Section, and the Continuity of its Flint 

 Floobings. 



By F. A. Bedwell, M.A., F.R.M.S. 



IN the summer of this year I laid before the Geologists' Association 

 some particulars of fourteen large Ammonites which I had found 

 in the Chalk cliffs east and west of Margate. The following is the 

 result of three weeks' further work on these cliffs. 



There are 89 Ammonites or remains of Ammonites to be seen 

 in situ between Cliff End, Birchington, and Kingsgate Bay. I 

 have marked on the cliff itself the position of each of the 89, by 

 placing on the Chalk a black cross thus + at a point on the eye level, 

 which is as nearly as possible " three yards to the eastward of a 

 perpendicular line passing through the Ammonite itself." When two 

 or more lie near each other, I have indicated the fact by adding dots 

 to the cross ; and in one case where I have removed an Ammonite, I 

 have placed a circle with a dot in the centre on the spot, and in 

 another instance in a cave the cross is placed close to the specimen 

 itself. I have measured the depth and height of each Ammonite, the 

 first relatively to a " datum line " and the second relatively to the 

 sand line. The '"'datum line " which I selected is the only one 

 available ; it is a line of nodular flints which is exhibited nearly con- 

 tinuously from Birchington to Kingsgate. It is in fact a line which 

 actually guided me to the majority of the Ammonite^ ; and although 

 it is in some places difficult to decipher, yet it has very distinct 

 characteristics of its own. It is nearly always double, and its indi- 



