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APPENDIX.
 

A.—Table showing the Yertical range of the Silurian Fossils of Britain.

In the Appendix to the Eirst Edition of this work, the range of those species
only which are common to the great divisions Upper and Lower Silurian was
exhibited in a tabular form. I am now enabled to give a complete list, so far
as our present knowledge extends, of all the species, and to particularize their
occm'rence in the Subdivisions of the System—thus foUowing the plan adopted
in the original ' Silurian System.'

Mr. J. W. Salter, aided by Prof. Mon-is, in the year 1859 compiled the Table
published in the last edition. In the reconstruction of the Table for the present
volume nearly 300 new forms have been incorporated with the previously known
Silurian Eauna. Several published species are omitted, because a careful ex¬
amination has shown their identity with others previously described. The list
now comprises all the hitherto well known British Silurian fossils, and shows
their range throughout the different subdivisions.

It is to be understood that Mr. Salter, who prepared the last edition of this
Table, is not responsible for any inaccuracies it may contain in its present form.
The additions and emendations have been chiefiy made by Mr. Etheridge, assisted
by Prof. Morris and Prof Jones. The student will observe that many of the long-
known names of Silurian fossils have been exchanged for more correct names
according to the recent determinations of their real aUiances, often obscure before,
and only estabhshed on the discovery of more perfect specimens, and by an extended
knowledge of extinct forms of life. To the palaeontological labours of Mr. Salter
and Mr. Davidson we owe many of the more exact recognitions that have lately
been made of the relationships of various TrUobites, Mollusks, and other fossils,
as well as many descriptions of newly discovered forms. See especially David¬
son's ^ Monograph on the Silmian Brachiopods,' and Mr. Salter's ^ Monograph of
the British Trilobites,' 'Appendix to Eamsay's Geology of North Wales,' &c. Mr.
Davidson has examined the list of published Brachiopods, and Dr. Duncan that
of the Corals; Mr. Carruthers has revised the Graptolites, and Mr. Henry Wood¬
ward the Eurypteridae ; and the improved nomenclature advanced by these and
other palaeontologists has been adopted in the body of the work. In the Expla¬
nations of the Plates, also, many of the old names wiU be found to have been
exchanged for others more correct as to generic and specific affinities, or entitled
to use by priority.

The Lingula-fiags (M. Barrande's ' Zone Primordiale' of the Silurian rocks,
' Primordial Sihman ' of the Table) have, as explained in the body of this work,
their fullest development near Tremadoc, Barmouth, and DolgeUy, in North
Wales, and in St. Bride's Bay, south of St. David's, on the west coast of Pem¬
broke in South Wales. In the Silurian tract of Shropshire they are, in my
opinion, represented by the dark schists which underlie the Stiper Stones, and
are superposed to the greatest mass of the Cambrian strata known in England
and Wales, namely, the Longmynd.

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