ANNIVERSARY ADDRESS OF THE PRESIDENT. 



exceedingly abundant in certain areas of the earth's surface, while 

 they appear to be wholly wanting in others. 



Still more remarkable are the relations which are found to exist 

 between the types of rocks occurring in different geographical areas. 

 The study of this subject is leading us to the recognition of the 

 fact that there are distinct penological provinces. In closely 

 adjoining areas — such as Hungary and Bohemia, for example — 

 widely different types of rock have been erupted during the same 

 geological period ; and this is a fact not less striking and significant 

 than that of the meeting of two perfectly distinct biological 

 provinces along a line which traverses the Malayan archipelago. 

 It cannot be doubted that the prosecution of this hopeful branch 

 of study — the geographical distribution of minerals and rocks — will 

 lead us to results of the highest interest and value. 



That there will be shown to be a distribution of rocks in time, as 

 well as in space, I am perfectly prepared to believe. I cannot but 

 think, however, that some of the generalizations on this subject 

 which have been hazarded are somewhat premature. To a geologist 

 ( especially one belonging to the school of Lyell) it is equally difficult 

 to conceive that there should be a broad distinction between the 

 metamorphic rocks of Archaean and post-Archaean age respectively, 

 as that the pre-Tertiary volcanic rocks should be altogether different 

 in character from those of Tertiary and Eecent times. 



The great object of all our studies (concerning the Morphology, 

 the Physiology, and the Chorology) of the mineral kingdom ought to 

 be to arrive at definite ideas concerning its ^Etiology — the causes by 

 which the existing forms, capabilities, and positions of minerals and 

 rocks have been determined. 



While the fossils contained in rock-masses afford us the means 

 for determining the date of their origin, the careful study of 

 the minerals which they include may enable us to unravel the 

 complicated series of changes through which they have passed since 

 their first formation. 



Eighteen years ago, when endeavouring to show how the origin 

 of a particular rock might be elucidated by a combination of studies 

 in the field, in the chemical laboratory, and by the aid of the 

 microscope, I ventured to offer to this Society some general remarks 

 on this subject. As it has been my constant labour ever since that 

 time to apply the principles then enunciated to the case of rocks 

 of more complicated character and more recondite origin, I may 



