136 
far up into Ellesmereland, generally consist of hard siliciferous limestone, and their 
decoraposition results in the heaping up of masses of augular fragments with no, 
or at least only very little fine material among them, i. e. they are dysgeogeuous 
after the terminology of Thurmann. The breaking off from a mountainside gene- 
rally is rather rapid, and an enormous talus may often be formed, but its physical 
nature is decidely averse to the development of vegetation, as the water will not 
be absorbed in it, even if the supply is large enough to give rise to a thriving 
vegetation on a more eugeogenous soil. Even the level gromid, the raarine terraces 
for instance, are mostly entirely devoid of finer materials at the surface, and only 
along the brooks narrow bands of vegetation are to be fomid, while the rest of the 
plain only supports a few lichens and perhaps some stray tufts of mosses. Rock- 
ledges and slopes which will, especially when favorably exposed, often be so very 
fertile on other strata, are also very poor in the regions of hard limestone, as the 
weatliering of the surface will constantly go on breaking them off and covering 
them with coarse material, thus never allowing the vegetation tirae for development 
and formation of humus. The limestones belonging to other systems generally are 
purer, or also argilliferous, and give rise to a far better soil. This in one of my 
reasons for doubting the Silurian age of the limestone forming most parts of 
Banks and Victoria Lands, where a vegetation exists that is rich in species, and 
rather luxuriant according to the relations of travellers in that region. Now this 
might perhaps also be attributed to the more southern site, but then even our 
knowledge of the stratigraphy of the western parts of the Archipelago speaks against 
the appearance of Silurian strata there. The extreme poverty of the flora of 
the Cornwallis Island district doubtless is not only apparent and due to deficient 
exploration, but in part actually caused by the nature of the soil of the hitherto 
alone explored southern islands of the group. 
About the arrangement of table V there are still a few points to explain. 
An alphabetical arrangement is preferred to a systematical one because it makes it 
easier to find a certain species in the long list. 1 have, however, thought it advis- 
able not to adopt the usual method of putting all species in one contirmous series, 
but to separate the different geographic groups already in compiling the list. Thus 
the connection of the species forming a group of similar distribution is far easier 
to muster and the necessity of enumerating them again and perhaps having to 
discuss a great many of them separately is avoided. Ten different groups are 
distinguished among the 204 species known from the Archipelago proper, the three 
species only recorded from Boothia Felix or the Melville Peninsula are excluded, 
likewise as, of course, all species of doubtful occurrence or value which should only 
have attributed to the derangement of the figures for the different groups and 
lessened their value. Even if some or other of these doubtful species should really 
have been found within the district it is noted for, I think it is safer to leave 
them out of consideration than to risk the false deductions they might give rise to 
