138 
THE GEOLOGIST. 
to wliich they add a by no means inconsiderable bulk, certainly sup- 
port, to some extent, 'M. Yirlet d'Aoust's hypothesis of the origin of 
organically formed oolite by means of ova, if not always due to insects' 
eggs ; and the entanglement of similar eggs in the clay of ponds also 
shows how insects may have exercised an agency, however slight, in 
the formation of some other stratified deposits. If to these evidences 
of insectal agencies, we add the probable fact, that the surfaces of 
many shales of various geological ages bear the trails of insects, as 
intimated above, pages 129 and 131, we have stronger proofs than 
we had heretofore of the wide-spread and long-continued existence of 
Insects in past ages of the world. 
To get better and clearer notions, we want more carefully observed 
and recorded tacts than we have hitherto had at command. Let ns 
get good observations on the crawling and burrowing creatures of 
the sea-shore and pool-sides, of sand- and mud-banks, and alluvial 
flats ; let us get good dried specimens or good drawings for compa- 
rison ; and let us carefully collect and collate fossil surface-markings, 
noting what are real surfaces and what are casts on the lower sides 
of the laminae and strata, and we shall then be doing good work 
towards the elucidation of Ichnolites of all descriptions. 
Before concluding, I must offer an observation on the ClimacticJi- 
nites WiJsonii, Logan, — a gigantic trail-like tract found in the Pots- 
dam Sandstone of Canada, and described and figured by Sir W. E. 
Logan, in the ' Canadian Naturalist and Geologist,' 1860, vol. v. p. 
279, etc. In this paper, Sir "William lucidly describes the probably 
littoral condition of the Potsdam Sandstone, extending for many 
miles along the old Laurentine Hills, and its evidences of tidal phe- 
nomena. The Climactichnites is associated at Perth, in Canada, with 
the Protichiites, tracks found also in other parts of the Potsdam 
Sandstone of Canada, and described by Logan and Owen in 1852, in the 
Geological Society's Journal, vol. xiii. p. 199, etc., plates G-14«. Of 
the Canadian Frotichnites, there are six different kinds or species, 
according to Prof. Owen ; they are all of large size, from about three 
to ten inches broad, and are referred to Crustaceans, possibly of the 
Limuloid type, that have crawled over the surfase of the saiid.* 
'Froticliniies of smaller size have been found in the Silurian rocks of 
Scotland, at Binks, Roxburghshire, by Prof. Iv. Harkness (' Quart. 
Journ. Geol. Soc.,' vol. xii. p. 213, fig. 2) ; and another, from the 
Coal-measures of South AVales, has been figured and described by 
Mr. Salter, in the ' Memoirs of the Geol. Survev, etc. : Iron-ores of 
South Wales,' 1861, p. 227, pi. 2, fig. 24. 
The Climactichnites is described as a trail about Gf inches broad ; 
and it is not dissimilar, in its transverse bars, to fig. \c of Mr. A. 
Hancock's plate (XIA^., see above, p. 131), illustrative of the natural 
gallery-track of the little sea-shore crustacean, Sulcator arenarius. I 
would suggest that the Climactichnital tracks were really infallen 
gallery-tracks, formed, like those of the Sidcator, by hurroimig Crus- 
* Simple narrow concave trails, also, are not wanting in the Potsdam Sandstone of 
Beaiiharuois. Canada. 
