Anniversary Address to the Royal Geologicul Society. 495 
possession of by first impressions and conclusions that they cannnot 
emancipate themselves from them. Romanes has compared these 
to Professor Mébius’ educated pike, who when he was thoroughly 
impressed with the fact that he was separated somehow by an 
invisible barrier from the minnows in the adjoining tank, could 
not afterwards unlearn his lesson though the barrier had been 
removed. So with these men; they cannot learn “when the 
hand of science has removed a glass partition.” 
It seems to me, therefore, that there should be more caution used 
in the comparison of supposed corresponding strata in different 
districts. Frequently there is a too direct and close correlation 
instituted between them, when they may have in reality no more 
than the general, but most important, connexion, that they were 
both formed, more or less probably, in about the same portion ofa 
certain geological period. It is frequently the too hasty gene- 
ralization respecting the formation of more or less nearly contem- 
poraneous rock groups, occurring in two different places, which 
leads to the supposition of a hiatus in one of the places, when it 
is found that the correlation of all the groups cannot be carried 
out. 
Geology seems, from the nature of the case, to fullow the course 
of other branches of knowledge. At first, ascertained phenomena 
form little more than an unarranged, undigested mass of facts. 
Afterwards these are put into order, and general connecting laws 
and principles, more or less correct, are deduced. Then, at a still 
later stage, it is found from further induction and more critical 
consideration of facts, that in many cases and respects generaliz- 
ation has been too sweeping and carried too far, and that it has 
to be limited and modified by subordinate and less obtrusive 
principles, so as to become more strictly scientific. Geology seems 
now to have reached this stage, at least as regards several of its 
branches. It is now not so much the bewildering variety of a 
crowd of uninterpreted phenomena which oppresses us, as the 
complexity of their relations, so many of which have been dis- 
covered. I would, therefore, respectfully enjoin upon my brethren 
of the hammer more circumspection than what they sometimes 
display, lest that by adhering too strongly to insufficiently guarded 
generalizations characteristic of an earlier stage of Geology, they 
may be contributing to the perpetuation of that stage, and uncon- 
sciously retarding the progress of discovery. 
