Presidenfs Address, 
9 
faith ; for mj own part, I have never hesitated to question 
a dogma from a divine if I thought he was wrong in his 
theology, and have now none in trying to refute these state- 
ments, believing, as I do, that geology is a science of facts, 
not of faith. Let us consider his first statement, " That 
all the consolidated strata, viewed chemically, bear marks 
of the subjection to an action of heat agreeable to the 
theory of the earth's refrigeration in direct proportion to the 
age of their deposit." Where the Kev. Mr Harcourt finds 
proof for this statement I have failed to see in his report. 
If he believes, as most geologists do, that the granite is 
the lowest rock we know in the crust of the earth, why 
can he not show the marks which bear evidence of greater 
chemical action at the base than is borne at the summit of 
the formation ? As I have said before, not being able to see 
any difference, mineralogically or chemically, in the struc- 
ture of granite, I am therefore bound to reject this portion 
of the statement. And now with regard to the second half 
of his first proposition, which states " That they [the rocks] 
show that action [meaning heat, or chemical action due to 
heat] most explicitly in the presence throughout, but more 
abundantly as the series descends, of that peculiar form of 
silica which is chemically reproduced by the action of 
heated volatile matter." Now, in dealing with this latter 
statement, I feel at a loss to see for one moment how the 
granites, the gneiss, and schist, and greywackes, bear evi- 
dence of being exposed to greater heat than we find ex- 
hibited in the Carboniferous epoch. 
I have already shown in my paper on the Aqueous Origin 
of Granite, that there, and also in traps, cavities exist, con- 
taining fluids which entirely fill the spaces at a temperature 
not higher than 94° of Fahrenheit, demonstrating that 
those cavities could not have been filled at a higher tem- 
perature. With this fact, along with others I have men- 
tioned, I cannot accept the latter portion of Harcourt's 
dogma. And I now beg you to remark, that the first dogma 
relates to the consolidated strata, the second only to igneous 
minerals ; let me repeat it : The igneous minerals were 
formed by molecular aggregation at a heat not exceeding, 
VOL. III. B 
