38 



but still reasoning entirely on paheontolo.sfical evidence, " the Lower Silurian of 

 America can be divided into two principal groups, one above the break at the base 

 of the Chazy, and the other below. The former includes the Chazy, Black River. 

 Trenton, Utica, and Hudson River formations. The lower comprises a series of 

 formation which are only now begining to become known." P^urther, Mr. Billings 

 says : " From the top of the Hudson River down to the base of the Black River 

 limestone there is no break, but all is occupied by a single immense, highly char- 

 acteristic and compact fauna. The lower, middle, and upper portions of this 

 series or group, as I should call it, may be easily recognized by species peculiar 

 to each, but the abundant and dominant forms are found throughout.' 



Between the Black River and Chazy there is a gap. These two formations 

 are connected by about twenty-three (23) species. Now, as there are, accord- 

 ing to Billings, only two species common to the Chazy and the Calciferous, there- 

 fore, on pal;\?ontological grounds, the break must be placed at the base of the 

 Chazy. As I have already said, there is no stratigraphical break at the base of 

 the Black River. What the structure indicates as between the Chazy and the 

 Calciferous I am not prepared to say as I have never examined the junction line 

 of these two formations. One of these lines appears to run from Grenville on the 

 Ottawa in an irregular line to Coteau Landing on the St. Lawrence, and another 

 from Gloucester and Metcalfe south of Ottawa to the vicinity of Edwardsburgh 

 on the St. Lawrence, but apparently much uncertainty exists as to the precise 

 nature of the junction of these two formations, and it would be both interesting 

 and useful to have the two indicated boundaries carefully traced out and studied. 



In my investigation of Canadian geology it has seemed to me most unfor- 

 tunate that such a stratigraphical expert and careful observer as Sir W. Logan 

 most undoubtedly was should have allowed his work to be so much influenced 

 by chemico-mineralogical theories and imperfect pala^ontological evidence. 

 Had he firmly held to the maxim of ni}' old friend and colleague, J. Beete Jukes, 

 late Director of the Irish Geological Survey, to the effect, as he expressed it, that 

 if " the fossils did'nt agree with the rocks so much the worse for the fossils,"' he 

 would probably have made no mistakes in the interpretation of the structure and 

 theafhnities either of the pakeozoic rocks of Lake Superior or of the Quebec group, 

 which latter, as it now stands depicted on the map, most certainly includes, not 

 only parts of the whole of the Cambro-Silurian and Cambrian formations as 

 developed in Eastern Canada, but also a very large area of strata which cannot 

 be otherwise regarded than as of pre-Cambrian or Archaean Age, probably Huron- 

 ian. I have roughly sketched out on this map the main structural features ot 

 the Quebec group region, but much laborious and careful work in the field is still 

 needed before the probable limits and distribution of the several formations of 

 the Cambrian and Cambro-Silurian systems can be laid down here as they have 

 been on the north-west side of the St. Lawrence valley. This region, how- 

 ever, extending from the Vermont boundary to Gaspe, offers an inex- 

 haustible field of study in all the most intricate probloms of dynamical and of 

 stratigraphical geology, and I hope some of our young geologist will, to use an 

 expressive Americanism, "go for it." Another very interesting question is to be 

 found in the determination of the limits of the ancient pahcozoic sea, in which 

 the deposits of the Ottawa valley were formed, and to what extent subsequent 

 denudation has removed the records of its existence over the Laurentian high 

 lands to the north of us. We already know of quite a number of small and now 

 isolated patches or outliers. Lake St. John, Lake Abittibe, and the Allumette 

 Islands, fifty miles up the Ottawa, and there may be a great many more in 

 his great northern unexplored region. These should be carefully sought 

 for, and we may yet find evidence to show that the now widely separated palivo- 

 zoic basins of Winnipeg, Hudson Bay, and the St. Lawrence were once connected 

 across the Laurentian Axis. At any rate, in theorising on these intricate questions 

 we must constantly bear in mind the unstable nature of what we call the earth's- 



