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 Fossils,' for which I hope to obtain very exten- 

 sive support. 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 those 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 ail my friends. 



S. J. MACKIE. 



27th May, 1864. 



