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Proceedings of the Koyal Society of Edinburgh. [Sess. 
Denmark and Sweden might afford information, I communicated with 
Professor N. V. Ussing of Copenhagen, and with Professor Holm and Dr E. 
Erdmann of Stockholm. These gentlemen most courteously sent me 
specimens from the principal horizons of the chalk in each country, and I 
desire to express my hearty thanks to them. Dr Smith Woodward, Mr 
Henry Woods, and Mr Jukes-Browne were also kind enough to send me 
specimens of Danish Chalk. But none of these will compare with the 
chalk of Belhelvie. 
They are all pure chalks laid down under conditions of sedimentation 
and of life dissimilar to those in the area in which the English Chalk was 
deposited. Nearly all are characterised by fragments of debris of Bryozoa, 
by the comparative scarcity of Foraminifera, and by the absence of shell 
fragments derived from Inoceramus. 
The chalk of Rtigen and the Upper Senonian of the Isle of Moen 
approaches most closely in general character to that of England. Thoiigh 
in both large fragments of Bryozoa occur, they contain also more Foramini- 
fera, and cells identical with those of A 5 and 6 are abundant. These two 
boulders are the purest chalks of the Belhelvie series and are probably the 
highest. That their chief ingredient should be cells similar to those 
occurring in the Upper Senonian of Riigen and Moen leads one to think 
that they may be of that horizon. 
Many of the Belhelvie boulders are ice-scratched, and it may be urged 
that they have travelled far. But in the brown, tough, unctuous clay in 
which they occur they are associated with pebbles of other rocks identical 
with or similar to the rocks of the district, and this, coupled with the fact 
that the whole series have an intimate connection with each other, makes it 
probable that they have not been moved a great distance. 
They could not be English Chalk, for they differ from it in important 
particulars : (1) in the quality of the arenaceous grains : felspars are more 
abundant, and the heavy minerals, zircon, rutile, and tourmaline, are less 
common and more worn ; (2) in the presence of free sponge spicules which 
yet retain the silica of their walls, though in altered condition ; (3) in the 
abundance of Radiolaria. 
Nor does chalk of a similar kind occur in English boulder clays. Mr C. 
Thompson of Hull was kind enough at my request to collect some thirty- 
five chalk boulders from the boulder clay of the Lincolnshire and Yorkshire 
coast ; these I have examined as well as chalk boulders from the clays of 
my own locality. But I have met with none that resemble either the 
Belhelvie boulders or the chalk of Sweden or Denmark. 
Nor can the Scottish boulders be compared with the white chalk of 
