[3] In this and subsequent remarks on fossil plants I shall often use Dr. Lindley’s terms, as most familiar in this country; but as those of M. A. Brongniart are much cited, it may be useful to geologists to give a table explaining the corresponding names of groups so much spoken of in palæontology.

[4] D’Archiac, Sur la form. Crétacée du S.-O. de la France Mém. de la Soc. Géol. de France, tome ii.

[5] D’Orbigny’s Paléontologie français, pl. 533.

CHAPTER XVIII.
LOWER CRETACEOUS OR NEOCOMIAN FORMATION.

Classification of marine and fresh-water Strata. — Upper Neocomian. — Folkestone and Hythe Beds. — Atherfield Clay. — Similarity of Conditions causing Reappearance of Species after short Intervals. — Upper Speeton Clay. — Middle Neocomian. — Tealby Series. — Middle Speeton Clay. — Lower Neocomian. — Lower Speeton Clay. — Wealden Formation. — Fresh-water Character of the Wealden. — Weald Clay. — Hastings Sands. — Punfield Beds of Purbeck, Dorsetshire. — Fossil Shells and Fish of the Wealden. — Area of the Wealden. — Flora of the Wealden.

We now come to the Lower Cretaceous Formation which was formerly called Lower Greensand, and for which it will be useful for reasons before explained (p. 282) to use the term “Neocomian.”

LOWER CRETACEOUS OR NEOCOMIAN GROUP.

MarineFresh-water
Upper Neocomian—Greensand of Folkestone, Sandgate, and Hythe, Atherfield clay, upper part of Speeton clay. Middle Neocomian—Punfield Marine bed, Tealby beds, middle part of Speeton clay. Lower Neocomian—Lower part of Speeton clay. Part of Wealden beds of Kent, Surrey, Sussex, Hants, and Dorset.
  1. Upper Neocomian—Greensand of Folkestone, Sandgate, and Hythe, Atherfield clay, upper part of Speeton clay.
  2. Middle Neocomian—Punfield Marine bed, Tealby beds, middle part of Speeton clay.
  3. Lower Neocomian—Lower part of Speeton clay.

In Western France, the Alps, the Carpathians, Northern Italy, and the Apennines, an extensive series of rocks has been described by Continental geologists under the name of Tithonian. These beds, which are without any marine equivalent in this country, appear completely to bridge over the interval between the Neocomian and the Oolites. They may, perhaps, as suggested by Mr. Judd, be of the same age as part of the Wealden series.