AMERICAN PUBLISHERS’ NOTICE. Vv 
been discovered in its lowest formation. By the positive proof thus 
furnished, Mr. Miller was convinced that the theory of a gradual 
progression in size, from the earlier to the later Paleozoic forma- 
tions, though based originally on no inconsiderable amount of 
negative evidence, must be permitted to drop. 
The fourth, fifth, and sixth editions were mainly if not wholly re- 
prints of the third. The seventh, which has just been issued under 
the supervision of Mrs. Miller, and is re-printed in the present vol- 
ume, contains large and interesting additions. While the text and 
notes of Mr. Miller are preserved without the slightest change or 
revision, some notes have been appended by a friend of Mrs. Miller, 
with the view of drawing attention to whatever modifications of 
opinion he may himself have recorded in his later works, or may 
have been known to express verbally in conversation with his 
friends. In addition to these, three or four notes have been fur- 
nished by the Rev. W. 8. Symonds, who is described as a well- 
known geologist intimately acquainted with the Silurian and Old 
Red of his own neighborhood in the south-west of England. Several 
new figures have also been added, taken either from specimens in 
Mr. Miller’s own unique collection, or from those in the possession 
of others, which it is known he had asked permission to copy. These 
present the fossils to which they relate in new and striking aspects. 
They are those on Plates ix., x., xu, and xiv., and on pages 54 
and 267. 
But the most important additions to the volume are from the pen 
of Hugh Miller himself. They consist of the Geologival Papers 
read by him before the Royal Physical Society of Edinburgh. 
These papers have been selected by Mrs. Miller from the mass of 
her husband’s unpublished writings; and, while they add greatly to 
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