256 The British Association at Newcastle. 
From the description and photograph of the bog described 
by Atkinson (2) the zonation is such as to indicate that a secondary 
succession has been initiated in the outer edge of the bog. The 
initial cause is undoubtedly fire, since this is the only agency that 
can remove the peat. The succession in the bog seems essentially 
like that of Minnesota. 
In concluding it may be stated that a sphagnum atoll is a bog 
whose outer edge has been partially destroyed. The only agency 
capable of both denuding and destroying the edge is fire. Fire 
occurs during or at the end of a prolonged period of drought when 
the water-level is low. The surrounding soil has no direct 
influence on the atoll formation, but since desiccation occurs more 
frequently and to a greater degree in sandy areas than in clay, 
atolls are more frequent in the former because fires are more 
likely to occur there. 
Grateful acknowledgment is due to Professor H. F. Bergman, 
who assisted in securing the samples of the atoll studied and who 
discovered and pointed out specifically to the writer the nature and 
location of the Hubert and Glenwood atolls. 
BIBLIOGRAPHY. 
1. MacMillan, Conway. “ On the Occurrence of Sphagnum Atolls in Central 
Minnesota.” Minn. Bot. Stud., Bull. 9, 1894. 
2. Atkinson, G. F. “ College Botany,” 1908. 
3. Shaw, C. H. “ The Development of Vegetation in the Morainal Depression 
in the Vicinity of Woods Hole.” Bot. Gaz. 33: 
435-450, 1902. 
4. Bergman, H. F., and Stallard, H. ‘ The Development of Climax Forma¬ 
tions of Northern Minnesota.” .Minn. Bot. Stud., 
4: 4, 1916. 
THE BRITISH ASSOCIATION AT NEWCASTLE. 
rpHE third “War” Meeting of the British Association was held 
at Newcastle, September 5-9. The botanical section met both 
morning and afternoon on Wednesday, Thursday and Friday, and, 
true to tradition, proceeded to Alnmouth for a field expedition on 
Saturday. 
One of the most important papers presented was that by Dr. 
Kidston and Professor Lang on a new fossil, Rhynia Gwynne 
Vaughani, from the sandstone horizon opened up by Dr. Mackie. 
This is fully described in the Transactions of the Royal Society of 
Edinburgh, and it is therefore sufficient to call attention to the 
special interest attaching to this curiously simple, much-branched 
Pteridophyte from so ancient an horizon. 
