INTRODUCTION. ix 
work; and if there be any blame for a further delay, he is not a sharer in it, and it must 
rest entirely with myself. 
After a joint tour of fourteen days through a part of South Wales, we parted, 
never I fear to meet again. My health, which had been wretched all the preceding spring, 
still continued in a state which made sedentary labour almost insufferable; and I did 
not come back to my academical residence till near the end of October last. At that 
time my friend J. Carter, Esq. (the Cambridge Secretary of the Palzontographical Society,) 
was employed in drawing up an Index of the fossils described in this work. This Index 
had a frequent revision, and required much time for its completion; but it was finished 
before the end of the Academic Term, and is now printed. For this kind assistance, 
which confers a great additional value upon the “Detailed Systematic Description of 
the Cambridge Palzozoic Fossils,” I am happy to record my warmest thanks. 
The previous historical sketch is my best and only apology for a long delay in 
the publication of this work, against which some of my geological friends, not without 
apparent reason, have more than once complained. But I have another reason for 
making these statements. Since 1849, Paleontology has made a rapid progress; and 
many excellent works have appeared on the Paleozoic Fauna both of Europe and 
America. A mere comparison of the dates of publication, without the explanation here 
given, might lead (and in one instance has led) to conclusions most unjust to myself, and 
injurious to my friend*. 
No other English writer has shown such a wide and accurate knowledge of Paleonto- 
logical literature, or so largely quoted from the works of those who preceded him; and this 
has been done by my friend, not from ostentation, but from an earnest wish to do full justice 
to those who had written on any of the difficult subjects which are treated of in this work. 
In the multitudinous details of the following pages, there is not, I most confidently affirm, 
one genus or species claimed by Professor M’Coy as his own to which he did not believe 
himself entitled when the pages were struck off. At the same time it is possible that, 
spite of an honest desire to do full justice to every one who had written upon the Pale- 
ozoic fossils, he may, in some rare instances, have failed from want of knowledge, and 
given his own name to a species that had been published before by another. This must 
be the almost inevitable fortune of one who writes, at great length, upon a rapidly 
progressive science; and conflicting claims of this kind, when fairly advanced, are very 
easily adjusted. 
I am certain that my friend has many times, during the progress of this Volume, made 
a sacrifice to it of the credit he might have gained by an immediate publication of his 
* J here allude to a charge insinuated against myself, as Curator of the Cambridge Museum, of want of liberality ; 
and a more severe charge against Professor M°Coy of disingenuous suppression. To both charges (published by the 
Palcontographical Society, British Fossil Corals, Part m1. 1852, pp. 150, 151) I have replied, in two papers, published in the 
Annals and Magazine of Natural History, for April and September, 1854. No satisfactory answer has been, or can be 
given to my plain statements. The original charges, if advanced as statements of fact, are put in such a form as to be 
untrue: if they are insinuated as matters of opinion, they are uncourteous and unjust. 
b 
