of the Placoid order in the Yorkshire Coal Field : Gyracanthus, 
Hybodus, Pleuracanthus, Ctenoptychius, Helodus, Ctenodus, 
and Diplodus. In conclusion, the author remarked, "I have 
now endeavoured, even at the risk of being tedious, to bring 
into one view the scattered fragments of our knowledge of 
the fossel Ichthyology of this district, and have attempted to 
assign to each element of this knowledge its proper position 
in the large Zoological group of fishes ; it must, however, 
be evident, that we have as yet but entered upon the very 
threshold of the investigation. Much, very much remains 
to be accomplished before we have completed even the first 
stage of the inquiry, namely, the determination of all the 
genera and species of fishes which exist in the neighbouring 
strata, and the distinguishing characters of each. In this 
extensive work, a work of no little labour, the combined 
exertions of many are required. All members of this 
society, and the public in general, are able to co-operate in 
the work ; if not in the investigation and determination of 
species, at least in providing materials for observation, by 
the collecting and contributing of specimens. And when, 
by combined exertion, this part of the science is so far 
advanced, that we can from a small fragment pronounce with 
certainty to what species it belonged, then may be pursued 
with advantage and eff'ect the second and ulterior depart- 
ment of the fossil Ichthyology, namely, the determining of 
the precise range and circumstances of distribution peculiar 
to each individual species. Towards this latter branch of 
the inquiry, the mere amateur in Geology like myself, who 
has only cultivated the science, or rather the Zoological 
department of it, as an occasional relaxation from his 
ordinary pursuits, can do but little. For its accom- 
plishment we must look to those gentlemen (many of whom 
I have now the honour of addressing) whose very profession 
is Geology ; whose daily avocations lead them into the 
interior of the earth ; and whose education, and habits of 
patient and accurate observation, eminently qualify them 
for the task. When the Fossil Ichthyology of the district 
in this its most extended sense, is thoroughly investigated, 
we may with confidence expect that many and valuable 
will be the practical applications of the information thus 
obtained ; nor will the results be limited in their interest to 
this densely peopled district ; Geological science in general 
will have received a precious boon ; some light will have been 
thrown upon the history of that most interesting to man 
of all the geological epochs, the carboniferous era ; and we 
may be allowed a clearer view of the wisdom, and the 
power, and the goodness of Him, who, long anticipating the 
wants of man, first made the iron and the coal, then sunk 
them safe and deep beneath the accumulating sediments of 
countless ages, ana in his own appointed time, by his 
