35 



succeeding generatioiiiJ. The geological map ofCauida, which Illustrates »ir W. 

 Logan's work, is unfortunately wen less widely known and distributed. It is 

 rarely to be met with in any public institution, and I doubt whether more than 

 100 or 150 copies have ever found their way to Canada. Under these circum- 

 stances, and as there is not very much to be said in regard to the general paheozoic 

 stratigraphy immediately around Ottawa, it will, perhaps, be more interesting 

 if I attempt this evening to give a brief explanation of the main stratigraphical 

 features of eastern Canada, as shown on the map, and point out some of the ques- 

 tions which seem to require for their final solution more careful and systematic 

 investigation than they have yet received, work which must be done, however, 

 not in the museum but in the field. If my observations are somewhat desultory 

 I must ask j^ou to bear in mind that I am not giving a lecture, but only an in- 

 formal geological talk, and that I would much prefer not to have all the talk to 

 myself, but to hear any remarks, observations, or suggestions that it may occur to 

 the members of the Club to interpolate. With your permission I propose first 

 to make some remarks on the subject of geological nomenclature, and to explain 

 the sense in which I use certain terms, such as formation, system, series, &c.. 

 and also the use I propose to adopt in future for the names Cambrian and Silu- 

 rian. The former, though perhaps the older of the two, is scarcely recognized 

 by a large number of American geologists, and its use by the British Geological 

 Survey has been restricted to certain strata, which probably correspond to the 

 base of the Atlantic Coast series of Nova Scotia, and to the lowest of the palajozoic 

 formation of the Ottawa valley. In Januaiy, 1836, Sir Roderick Murchison, in a 

 communication to the Geological Society of London, gave an account of the 

 origin of the terms Cambrian and Silurian. In 183G, the term Cambrian included 

 all the formation below what Murchison had called Llandeils (Calci/erous and 

 Chazy), and he and Sedgwick supposed that the rocks of North Wales and 

 south-western South Wales, which the latter was then studying, were older than 

 the Llandeils, and to these the name Cambrian was assigned by Sedgwick ; but 

 later much of what had been included in Sedgwick's Cambrian turned out 

 to be really not older than the Llandeils (Silurian of Murchison), and in this way 

 came about the undue extension of the term Silurian, and the e(j[ually undue ex- 

 tinction of the term Cambrian. However, so long as we understand what is meant 

 by the names when used the object is served, but it is very perplexing when every 

 geologist us^is them in a different sense, according as they are p<irtizans of the 

 one or the other of the eminent authors of the name. I am desirous, therefore, 

 that in Canada at least some definite, and if possible uniform action should be 

 established in this respect and also in the colours and notations of the Geological 

 ^Survey, and with this object in view I have constructed the Index Chart which 

 you see here, with some brief explanatory notes to accompany it. I propose to 

 leave copies of these for reference by members of the Club, and if there are no 

 very weighty objections against the proposed scheme, I hope it will be adopted 

 in future by Canadian geologists, and I also hope tliat anyone who has objections 

 to urge will come forward and state them, and in doing so wilf also be prepared 

 to suggest the way in which the objection can be met and the scheme improved. 



In speaking of the Ottawa valley I must not be understood to refer to the 

 whole of the vast region, some 80,000 square miles, drained bv the Ottawa and its 

 tributaries, but only to the slightly undulating area, about 6,250 square miles, 

 extendin,' from the longitude of Montreal westward to Calumet, which is bounded 

 on the north by the hills and ridges that form the southern slopes and si)urs of 

 the Laurentide Mountains, and on the south by the much more elevated peaks 

 of the Adirondacks in the State of New York. These two hilly region.s, entirely 

 composed ot ancient crystalline rocks, aie connected on the south-west by a low 

 ridge across which the St. Lawrence has found a passage from Lake Erie into the 

 Ottawa val'ey and which now forms the picturesque .scenery of the Thousand 

 Islands. Proceeding eastward, to the vicinity of the Lake of the Two Mountains, 



