79 
conclusion. Transfusion of silica in solution, and titan- 
iferous and chlorine-bearing vapours or solutions would 
provide the conditions necessary for the formation of the 
minerals found in the field. A later circulation of heated 
juvenile waters appears to have exercised a selective action 
upon the outer edge of the altered zone, causing serpen- 
tinization of diopside and tremolite, and even at one point 
forming a vein of asbestos from the serpentine. But while 
the mineral assemblage found in this locality may be 
thus explained, no process for the formation of those 
detailed and beautiful structures which led to the Eozoon 
controversy is known. 
HISTORICAL OUTLINE. 
Though this is not the locality where Eozoon was 
first discovered, it has furnished some of the best specimens 
and it was in specimens obtained here that Sir J. W. 
Dawson found the structure which he called Eozoon cana- 
dense. It was first noticed in a specimen from Burgess, 
Ontario, and was found in place in 1858 at Grand Calumet, 
Quebec, by Mr. McMullen, of the Geological Survey of 
Canada. Collections from Cdéte St. Pierre were made 
between the years 1863 and 1866 by Mr. J. Lowe, of the 
Survey. Extensive collections were made by Sir J. W. 
Dawson and Mr. T. C. Weston, between 1873 and 1877. 
A great many of these examples were sectioned, carefully 
examined and faithfully described by Sir J. W. Dawson 
and Dr. W. B. Carpenter in their final stand in support of 
the organic origin of the structure, which had been ques- 
tioned, in some cases by equally careful observers. The 
importance of the structure from a paleontological point 
of view, and its recognition in other countries, led to a 
re-examination of this area by Mr. A. Osann in 1899, 
under the auspices of the Geological Survey of Canada. 
In his report he described the igneous rock and its meta- 
morphic effects on the limestone. 
ANNOTATED GUIDE—Continued. 
Impure Grenville limestone is exposed in the 
left bank of Lievre river at Buckingham. Close 
to the water’s edge it contains thin bands of 
apparently igneous material, which have been 
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