896 
THE CRETACEOUS ROCKS OF BRITAIN. 
CHAPTER XXX. 
. ,|j 
THE MIDDLE CHALK IN SUSSEX. 
General Description. 
Tlie Chalk of Sussex was described in a general manner by 
Mantell, Dixon, and others, and many of the fossils which they 
so diligently collected must have come from the fine sections of 
Middle Chalk which exist in this county. But unfortunately 
they lived before the time when definite divisions or stages had 
been established in the Chalk of England, so that, except in a few 
cases where particular quarries are mentioned, there is no knowing 
which of their fossils were obtained from the Middle Chalk. 
Should any question arise, however, with respect to the exact 
horizon of certain of Mantell’s types it might be possible to deter¬ 
mine this by a microscopical examination of the matrix. Meantime, 
many of the old quarries are still open, and there are still collectors 
of Chalk fossils in Sussex; on them we would earnestly impress 
the necessity of recording the exact locality and horizon of every 
fossil they get, for without such a record such specimens are of 
little scientific value. Professor Ch. Barrois* was the first to give 
any adequate account of the Middle Chalk of Sussex, for he not 
only defined and described the several zones in the cliff section at 
and near Beachy Head, but he also visited the principal quarries 
near Lewes and those at Houghton in the Arun valley. From 
the fossils he collected at these places he came to the conclusion 
that most of the large series of Fish-remains from the Chalk studied 
by Mantell and Agassiz were obtained from the zones of the 
Middle or Turonian Chalk. 
About the game time the late Rev. H. E. Maddock, formerly of 
Eastbourne, collected diligently from the successive zones of the 
coast section, and he kindly placed his lists at our disposal. 
In 1884 Mr. C. Reid revised the Chalk and Tertiary areas of 
Sussex for the Geological Survey, tracing the boundary line of the 
Melbourn Rock and of the nodular chalk of the Holaster planus 
zone along the whole length of the South Downs. Some of the in¬ 
formation then obtained by him has been published in the Ex¬ 
planations of the Eastbourne and Chichester sheets of the 
Geological Survey,f and a few of his notes on other inland exposures 
have been incorporated in the following account. 
* Recherches sur le Terrain Cretace, pp. 16, 28, 33, etc. (1876). 
t The Geology of Eastbourne, Mem. Geol. Survey (1898), and Geology 
of the country around Chichester (1902). 
