Professor Bonney — Specimens from the Canadian Rockies. 293 



and not very well drawn), which on the whole are very like 

 the Desolation Valley markings, except that they are barely half 

 the diameter. Murchison, in the figure mentioned above, shows 

 the opening of the burrows to be * trumpet-shaped,' and Delgado 

 (" Etudes des Bilobites," pi. xxxix, fig. 1) represents Scolithus 

 burrows with a saucer-like depression at the top about* ^" in 

 diameter, in the middle of which is a low mamelon about half that 

 width at the base. This would produce a depression in a cast, though, 

 much larger in proportion than those in the mounds which I have 

 described, but that difference may be due to something in the material. 

 So I think it very probable these mounds indicate • pit-holes ' formed > 

 by the retreat into the mud of Scolithus or some annelid of similar 

 habits, and that, as remarked above, the pits were already filled, 

 perhaps a little stiffened, when Planolites moved among them, or, in 

 other words, that the pit-making worm lived in the mud and 

 Flanolites rather in the sand. But more evidence is needed before 

 we can speak confidently on this point. 



From Desolation Valley glacier Professor Collie also obtained 

 four specimens of darkish slaty rock, all probably more or less 

 calcareous, and one which is practically a limestone, not unlike 

 some dark varieties in the British Carboniferous Limestone. Of 

 two other specimens, one has a very pitted surface of a light 

 reddish colour, resembling a compact dolomitic limestone, perhaps 

 with some admixture of sandy material. Professor Collie states 

 that he finds Ca C O3 with some Mg C O3, and it effervesces but little 

 with cold H Cl.^ The second, whiter in coloui", but speckled with 

 dark green (possibly an iron silicate), is a quartzite. 



The last specimen brought by Professor Collie contains rounded 

 and subangular pieces, the former being the larger and occasionally 

 nearly one inch in diameter, scattered rather sparsely in a purplish- 

 red calcareous matrix speckled irregularly with the former material, 

 the weathered surface being very rusty. It consists of carbonates 

 of lime and magnesia, with iron oxide. A microscopic examination 

 shows the pale grey enclosures to be a fine-grained dolomitic 

 limestone containing a few granules of quartz or possibly a silicate ; 

 the cementing material of the matrix is also a dolomitic carbonate, 

 but is more irregular in its granular structure. In it two kinds 

 of grains are thickly scattered ; one being quartz, varying from 

 subangular to well rounded, some of which, at any rate, may be 

 regarded as wind-worn ; the other are more variable in shape, 

 enclosed in a dark ferruginous ring, and occasionally almost wholly 

 stained by it. Some have green centres, which show an aggregate 

 structure with crossed nicols, and are probably a variety of 

 glauconite ; others resemble the lai'ger fragments, but are a little 

 finer grained ; a few apparently retain traces of a reticulate structure 

 (possibly crinoidal) ; two or three thin elongated or curved objects 

 may be fragments of mollusca, and one suggests a spiral foraminifer. 



Thei'e is no precise evidence as to the age of any of these 



1 The chemical notes throughout are the results of Professor Collie's qualitative 

 examinations. 



