106 REPORT— 1872. 



■with that of Ilenncqucvillc, near Troiiville, which seems to belong to tlio " Pcrche " 

 system, and of which tlie Ilavre beds are au exteusiou. The second fold seems 

 to poiut towards the Isle of Wight, where another dislocation from east to west 

 seems to have crossed it. The third and fourth, those of Bray and La Bresle, do 

 not appear to extend to the Hampshire basin. 



Piirallelism of the French and English Chalk. — The English chalk, taking the 

 chalk of the Kentish coast from Folkestone to St. Margai'et-on- Cliff as the type, 

 would be thus grouped so as to correspond with the diyisions established by 

 M. llebert in France. 



I. Taking the Gault as the base of the chalk, on which point all are agi'eed, the 

 1st diyisiou of the chalk would be formed by the Upper Greensand, " gres vei-t 

 superieur," which is the snme at Folkestone, Havre and Fecamp, and elsewhere. 

 Tlie grey chalk (cruie (/rise) which coyers it is identical with that of Rouen j the 

 Ammonites varians, Mantclli, and rhutomagcnsis which are there found, leave no 

 doubt ; and it is recognized that in France the same fauna exists in the Upper 

 Greensand and the grey chalk, and that these two rocks alternate. These two 

 diyisions woidd form one, as La Craie Glauconiei<se. There may be some difficulty 

 in separating the grey chalk from the chalk marl. 



II. The grey chalk is covered at Folkestone as in France (generally) by a very 

 nodular chalk without flints, and with grey argillaceous veins, containing Inocc- 

 ramus kihiatus (Tn-ongniavt), Ainmoniics nudosoides (iichlniev), Echinoconus siibro- 

 fuiidifs, Sec. This forms the second division of the chalk. The difference of the 

 fauna of this from tliat of the underlying bed is almost complete. Sometimes, as 

 Mr. Whitaker has observed, and has kindly furnished M. Hebert yvith his views, 

 at the bixse of this nodular chalk is an argillaceous bed witli Belemnites, which is 

 most likely the £. pleniis of Blainvilie. This bed is found in Shakespeare's CUff, 

 and has also been recognized in France in several places, more especially at 

 Neufchatel in Bray and Boulogne. It forms the base of the di-^ision termed 

 Craie a Inoceramus lahiatus. The junction of this bed of argillaceous chalk with 

 the underlying grey chalk will be found to be marked by a hardened and eroded 

 surface, which is pierced by holes. 



At Dover the thickness of the chalk without flints, with Inoceramus lahiatus, 

 may be considered from 12-j to 140 feet, to which should be added about 80 feet 

 of the chalk with flints lying above it in the eastern clifl's of Dover, <as they contain 

 exactly the same ftiuna. This division, like the former, is always terminated b}' one 

 or more hardened and pierced surfaces. 



III. The next 13-j feet in thickness consist of a series of hard nodular beds, 

 containing beds of flint, the principal fossils of which are Holastcr planus (in the 

 lower part) and JIulaster placenta (above) ; Ananchtjtes f/ihba is also very common, 

 as well as Micraster cor-testiidinarium, vrhich gives the name to this division. The 

 lithological character is also well marked. It is seen just at the clifl' to the south 

 of St. Slargaret, at the level of the sea, and is there rich in fossils. 



IV. Above the last-named hard chalk, a soft challc, often quite of a mealy aspect, 

 forms the upper part of the northern cliffs of Dover and the whole of the clift' north 

 of St. Margaret. This should be referred to the chalk with Micraster cor-angvimim, 

 abrmdant at Gr.avesend, but badly preserved at St. Margaret. 



Y. A division characterized by the presence of Belemnites mucronatm, does not 

 exist in Kent, but only in Xorfolk. 



It is very important to observe that each of the principal limits assigned to these 

 divisions corresponds in France with the places of thick beds which"^ are yvauting 

 in England. Thus between the Craie Glauconieuse and the chalk marl with Inoce- 

 ramus lahiatus, the great series of the sandstones of Maine and the limestones with 

 Ichthyosarcolytes is interposed. These beds are abstnt in the north of France 

 and Gerinany, as well as in England ; also between the chalk marl with Inoceramus 

 lahiatus and the chalk with Micraster cor-testudinarium, as described above, the 

 great mass of the hippuritic limestones should be placed. This also does not occur 

 in the northern countries. These remarks prove that the stratigraphical limits 

 which have been described indicate great breaks in the sequence, of long duration, 

 when no remains were deposited in the north of Europe. 



B 



