138 



THE GEOLOGIST. 



to which they add n 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 facts than we have hitherto had at command. Let us 

 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 laminse 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 Climactich- 

 nUes Wilsonii, Logan, — a gigantic trail-like tract found in the Pots- 

 dam Sandstone of Canada, and described and figured by Sir Yf . 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 Rills, and its evidences of tidal phe- 

 nomena. The ClimacticJinites is associated at Perth, in Canada, with 

 the ProticJinifes, 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-14a. Of 

 the Canadian Protichnites, 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 

 Liimiloid type, that have crawled over the surfii^e of the sand.* 

 Proliclniilcft of smaller size have been found in the Silurian rocks of 

 Scotland, at iJinks, Roxburghshire, by Prof. E. Harkness (' Quart. 

 .louiMi. (Jcol. Soc.,' vol. xii. p. 213, fig. 2); and another, from the 

 Coal-iiu^asures of South Wales, has been figured and described by 

 ]Mr. Salter, in the ' Memoirs of the Geol. Survey, etc. : Iron-ores of 

 Soutli AVales,' 18GI, p. 227, pi. 2, fig. 24. 



• The CJ'nuariiclniiIrs is described as a trail about 6| inches broad; 

 and it is not dissimilar, in its transverse bars, to fig. 1^? of Mr. A. 

 Hancock's platp (XIA^, see above, p. 131), illustrative of the natural 

 gallery-track of the little sea-shore crustacean, Sulcator arenarius. I 

 would sugg(^st that the Climactichnital tracks were really infalleu 

 gallery-tracks, formed, like those of the SnJcafor, by lurroicing Crus- 



* Simple tiarixnv concave trails, also, arc not wauling in the Potsdam Sandstone of 

 Bciauharnois, Canada. 



