iv 
PREFACE. 
to supply useful materials for the labours of others, and to do some- 
thing myself also for the advance of a very imperfect but very noble 
science. 
There is one labour — the first part of the first instalment of which 
will appear, I believe, on the 1st of July — my projected * Illustrated 
Catalogue of British Eossils,' for which I hope to obtain very exten- 
sive sui^port. The printing of the first portion, complete in itself, 
* An Illustrated Catalogue of British Fossil Sponges,' has already 
been commenced, and in it the original figures, descriptions, and biblio- 
graphy of all the described British fossil species will be given, with 
original notices of tliose new kinds which have already come to my 
knowledge, or may hereafter do so before the completion of the 
volume. As this work will be exceedingly full, it will entail a very 
heavy outlay on the publisher, not to be compensated, unless those 
geologists, who are not sponge-collectors, come freely to its sup- 
port, in the faith that the success of this gigantic undertaking can 
only be accomplished by mutual help, if ultimately every depart- 
ment of British Palaeontology is to receive similar illustration. 
All but my last words are penned ; I devote them to my best 
wishes for the welfare of all my friends. 
S. J. MACKIE. 
Ttth May, 1864. 
