Geological Survey of Canada, 67 



interests of the country would suffer from lack of tins kind of 

 knowledge. There is besides a vast amount of drudgery to be 

 done, which no amateurs will ever undertake, but the execution 

 of which opens up the way for them. The writer has himself 

 worked at some little points of Canadian geology, of which, but 

 for the labours of the Survey, he would perhaps not have known 

 the existence, and from which these labours had already removed 

 the preliminary difficulties. A stimulus is thus given to ori- 

 ginal investigation by -private persons; and there are not yet 

 enough of labourers to occupy the openings already presented. 

 Not to be tedious in this matter, we hope what Sir William 

 Logan is now doing for Canadian palaeontology will be appre- 

 ciated in such a manner as to induce him still more extensively 

 to prosecute this very important department of his work. 



Prof. Hunt's portion of the Report is occupied with two dis- 

 tinct subjects ; — one, a contribution to the solution of an intricate 

 problem in theoretical geology which has more or less baffled 

 previous enquirers; the other, an enquiry into the value of lish 

 manures and the inducements to their manufacture in Canada. In 

 the first part Mr. Hunt has summed up the principal facts in the 

 history of dolomites or magnesian limestones, and has described 

 with many analyses -a great number of there rocks occurring in 

 various formations in Canada. He then considers the theories 

 which have been proposed to explain the formation of these rocks, 

 and rejecting them all as untenable, maintains that the carbonate 

 of magnesia was precipitated mixed with carbonate of lime, and 

 finally united directly with it to form a dolomite. The conditions 

 of this precipitation are illustrated by a series of experiments 

 upon the action of solutions of bi-carbonate of soda on sea-water, 

 and of bi-carbonate of lime upon waters holding sulphate of 

 magnesia. In the latter case by an unexpected reaction there 

 are formed under certain conditions, gypsum and bi-carbonate of 

 magnesia. These researches form a part of a series of investiga- 

 tions in which Mr. Hunt is engaged on the chemical conditions of 

 geological deposition and metamorphism, and which we hope he 

 will one day combine in a systematic treatise on the subject. 



Of the second subject, the fish manures, we shall attempt no 

 summary, as the paper itself is reprinted in this number. It 

 should be copied into all the agricultural journals, and extensively 

 circulated. The three tacts, that in all the old and run-out soils 

 of Canada, phosphates and ammonia are urgently required ; that 



