sand,
clays, and gravels, and attaining a very considerable thickness
(_Bag-shot and Bracklesham beds_). The superior portion of the
Middle Eocene of Britain, on the other hand, consists of deposits
which are almost exclusively fresh-water or brackish-water in
origin (_Headon and Osborne series_).

The chief Continental formations of Middle Eocene age are the
"Calcaire grossier" of the Paris basin, and the "Nummulitic
Limestone" of the Alps.

(3.) UPPER EOCENE.--If the Headon and Osborne beds of the Isle
of Wight be placed in the Middle Eocene, the only British
representatives of the Upper Eocene are the _Bembridge beds_.
These strata consist of limestones, clays, and marls, which have
for the most part been deposited in fresh or brackish water.

II. EOCENE BEDS OF THE PARIS BASIN.--The Eocene strata are very
well developed in the neighbourhood of Paris, where they occupy
a large area or basin scooped out of the Chalk. The beds of this
area are partly marine, partly freshwater in origin; and the
following table (after Sir Charles Lyell) shows their subdivisions
and their parallelism with the English series:--

GENERAL TABLE OF FRENCH EOCENE STRATA.

UPPER EOCENE.

_French Subdivisions._ _English Equivalents._
A. 1. Gypseous series of Mont 1. Bembridge series.
Montmartre.
A. 2. Calcaire silicieux, or 2. Osborne and Headon series.
Travertin Inferieur.
A. 3. Gres de Beauchamp, or 3. White sand and clay of
Sables Moyens. Barton Cliff, Hants.

MIDDLE EOCENE.

B. 1. Calcaire Grossier. 1. Bagshot and Bracklesham beds.
B. 2. Soissonnais Sands, or 2. Wanting.
Lits Coquilliers.

LOWER EOCENE.

C. 1. Argile de Londres at base 1. London clay.
of Hill of Cassel, near
Dunkirk.
C. 2. Argile plastique and 2. Plastic clay and sand with
lignite. lignite (Woolwich and Reading
series).
C. 3. Stables de Bracheux. 3. Thanet sands.

III. EOCENE STRATA OF THE UNITED STATES.--The lowest member of
the Eocene deposits of North America is the so-called "_Lignitic
Formation_," which is largely developed in Mississippi, Tennessee,
Arkansas, Wyoming, Utah, Colorado, and California, and sometimes
attains a thickness of several thousand feet. Stratigraphic