Review of Recent Geological Literatiwe. 55 
may perform a geological part in nature by disintegrating the 
schistoid rocks, which enter into the constitution of arable soil. 
The examples cited and described show therefore that the pro 
duction of mineral deposits by plant life is neither a rare nor an 
insignificant phenomenon of chemical geology, and is further 
proof that very important geological results are often achieved by 
the most lowlv organized forms of life. 
REVIEW OF RECENT GEOLOGIC \\ L 
LITERATURE. 
On bwrrows and tracks of invertebrate animals in paleozoic rocks, anil 
other markings. Sin J. W. Dawsox. (Quart. Jour. Geol. Soc, Nov.. 
1890, vol. xlvi.) 
This paper consists of critical notes and comparisons, illustrated by 
graphic reproductions (from photographs) of several of the problemat- 
ical markings that are familiar to the geologist under the names of 
Bilobites, Protichnites, Climachtichnites, Scolithus, Arthrophychus, 
etc., and which are very often hastily grouped under the comprehensive 
and vague term •'fucoids." The author has made use of the abundant 
material of this nature belonging to the Peter-Redpath museum at 
Montreal, collected by himself at the time of the enlargement of the 
Grenville canal, on the Ottawa river, and added since by Lt.-Col. Grant 
from the vicinity of Hamilton, Ontario. 
The author considers six genera as the burrows and tracks of marine 
animals, probably crustaceans, as he had pointed out in 1864 (Can. 
Nat. n. s: vol. i, pp. 363. 458), viz.: Rusichnites, Arthriehnites. Cruzi- 
ana, Climachtichnites, Frama, and Crossochorda. The first two are 
names substituted respectively for Rusophycus, of Hall, and Arthro- 
phycus, of Harlan. 
Different generic names have been given to some tracks closely related 
which the author would apparently regard as unworthy of generic rank, 
as they exhibit a variability that seems dependent on t lie nature of the 
sea bottom, or on the various modes of progression. They pass into 
Protichnites, of Owen, and into the worn tracks of the genus Nereites, 
of Hall. The same trail sometimes passes through the dtfferenl charac- 
ters of Cruziana, Crossochorda. and Nereites, though Nereites was sup- 
posed by Hall to be formed by molluscs. He shows by comparisons with 
tracks of modern Limulus, polyphemus that both the Protichnites and 
the Climachtichnites may have been formed by some of the earlier crus- 
taceans which had a divided and truncated tail. This would account for 
the ridge sometimes dividing the furrows and transverse ridges, ami for 
