74 HOUX EXPEDITION — GENERAL GEOLOGY. 



EXPLANATION OF PLATES. 



Index to Signs on the Sections. 



Pre- Ca>nbri(in — 



a. gneiss. 



^. mica-schists. 



y. quartzite. 



Eruptive Dykes (granite, etc), x. 



Ordoviciaii — 



a. quartzite. 



/'. Sandstone. 



c. Dolomite. 



d. Fossil if erous Limestone. 



e. clay slate. 



f. Micaceous Slates. 



g. Mudstone witii cu})es. 



Post-Ordflvician Co>ii^Ioi>ie?-ates. o. 

 Recent alhn^iiim. W 



(Figures 3, 8, 9 and 10 drawn l)y R. Tate; Figures 1, 2, 4, 5, 6 and 7 drawn by 



J. A. Watt). 



Plate I. 



Fig. 1. — Section across McDonnell Ranges in the meridian of Ellery Creek. 



Vertical scale - - - - 2000 feet to 1 inch. 

 Horizontal scale . - . 2 miles to 1 inch. 



„ 2.^Section across South McDonnell Range, near Heavitree Gap. 

 Vertical scale - - - - 1000 feet to 1 inch. 

 Horizontal scale - - - 800 yards to 1 inch. 



„ 3. — Belt Range seen from the south, showing Oidovician sandstone and 

 quartzite resting unconformably on Pre-Canihriaii gneiss and mica- 

 schist. 



^^ 4. — Section of Ordovician Strata north of George Gill Range. 



Horizontal scale - - - 1 mile to the incli. 



Vertical scale - - - 500 feet to tlie inch. 



