HORN EXPEDITION — GENERAL GEOLOGY. 55 



more .strictly, Ijy soft ai-gillacooiis limestone, :\.\n] this liy jiaid red limestone 

 comparatively free fi'oni ai-giilaceous matter, and tiiis lattei' Ijy a great tiiickness of 

 sandstones and quartzites. The lowest strata, an<l those first deposited, hear 

 indications of shallow water deposition, probably on a sinking sea-bottom. Tlic; 

 next strata, the limestones, point to deeper water conditions and practical 

 quiescence, although the water still remained muddy, as evidence Ijy the some- 

 wliat argillaceous character of the limestone, and by the pi-esence of trilobites and 

 rarity of corals. The strata next in ascending oi'der indicate upheaval and 

 deposition in sliallower water, these strata being much less calcareous and more 

 argillaceous than the preceding limestone. Lastly, on top we have a great thick- 

 ness of sandstones, the uppermost layers especially, which are ripple-maiked to 

 such a great degree, and wliich contain peljble bands, as in the (Jlen of Palms, 

 Laurie's Creek, etc., pointing to deposition in very shallow water. 



Di/>. — Tlie strata of the Oi'dovician .system dip at very vaiying angles. As a 

 general rule, however, it may be said that the dip increases as we go nortiiwards. 

 This has its explanation in the more highly-disturbed state of the rocks in the 

 northern portion of this area. The three following seiies of observations on the 

 dip of the strata will give some idea of the steady incrc^ase in the angle of inclina- 

 tion of the strata in a section across one arm of a fold : — 



1. Levi Range northwards for a distance of about four miles 9°, 14°, 14° 30', 

 17°, 22°, and 37°. 



2. From ]>owsen's Hole in a N.W. direction. At Bowsen's Hole the dip was 

 10°; at 3 miles was 15° -20°; at 4, 30°; at G, 35° -40°; at G|, 45° -50'; at 8, 

 70°; at 81, 75° ; at 14, 80°. 



3. At the western extremity of the Mereenie escarpment, wlilch constitutes tlie 

 wall-like southern boundary (rising to nearly 1000 feet) of Horn Valley, the dip of 

 the fossiliferous limestones is 37° 8. 5° W. At the entrance to Stoke's Pass (three 

 miles due north) the dip of the quartzite, wliich forms the northern w.ill of Horn 

 Valley, was found to have increa.sed to 00°; and that of the underlying beds to 

 increase still further to their northerly termination. 



(e) Detailed Sections. 



1. Section through Levi and James Ranges {vide Section McDonnell 

 Range to Levi Range). A traverse across Levi Range revealed the fact 

 that the sandst(me composing this range has the form of a shallow .synclinal 

 trough. Levi Range lias a steep escarpment on its north and south faces 



