1897] NOTES AND COMMENTS 295 
Esthonia seem to have been more successful than that to the Ourals, 
owing to the difficulty of transporting the larger number in the 
latter case. Those who visited Finland had an opportunity of test- 
ing the classification of supposed Archaean rocks recently put.forward 
by Mr J. J. Sederholm (see Natural Science, vol. x. 1897, p. 79). 
The general opinion seemed to be that the evidence was insufficient 
to warrant the ascription of an Archaean age to many of the rocks. 
Under the leadership of Baron de Geer the glacial phenomena of 
the district were studied, and the Asar, with ek many English 
geologists made their first acquaintance, gave rise to interesting dis- 
cussions. The main object of the Esthonian excursion, eden the 
direction of Akademiker Friedrich von Schmidt, was the examination 
of the Cambrian, Ordovician, and some of the Silurian rocks of the 
Province. The junction of Ordovician and Silurian was not over 
easy to follow under the conditions of the excursion, but the grand 
series of absolutely unaltered Cambrian with Platysolenites, Olenellus, 
Obolus, and Dictyonema, was a revelation to many. The party had 
also the advantage of the presence of A. von Mickwitz, whose palaeon- 
tological work in these Cambrian beds has been of the highest value. 
At the Congress itself, if no practical results were arrived at, 
still many discussions on matters of general importance to geologists 
took place. The main problem put before the Congress was the 
classification and nomenclature of rocks, both stratified and igneous, 
but chiefly the former. Treatises by Messrs Frech, Bittner, Walther, 
and Loewinson-Lessing formed the basis of discussion. This re- 
sulted in the following resolutions: “The Congress is of opinion 
that the historical method of classification must be adhered to, 
though it should continually be made more natural. The council 
is to nominate a committee to study the principles of classification in 
this spirit.” “The introduction of a new stratigraphic term into 
international nomenclature should be based on a clearly defined 
scientific necessity supported by peremptory reasons. The appella- 
tions applied to a terrane in a definite sense cannot be applied in 
any other sense. The date of publication is to decide the priority 
of stratigraphic names given to the same series of beds.” <‘‘ For the 
minor stratigraphical divisions, sufficiently characterised palaeonto- 
logically, in the case of the creation of new names, it is preferable to 
take as their basis the most important palaeontological characteristics, 
Geographical or other names should only be used for divisions of a 
certain importance containing many palaeontological horizons, or 
when the terrane cannot be characterised palaeontologically.” “Names 
badly formed from an etymological point of view are to be corrected 
without excludingthem from the domain of science.” Certain proposals 
of minor importance were referred to the above-mentioned committee. 
There is no doubt that with the advance of geological knowledge 
