GEOLOGY OF THE COOMA DISTRICT, N.S.W. 207 
mence three-quarters of a mile from the creek, and forma 
very striking feature of the topography, extending half a 
mile to the south and much farther to the north. They are 
composed principally of boulders and pebbles of brown 
quartzite and white quartz. The quartzites are up to 18 
inches in length, and there are occasional boulders of nearly 
three feetin diameter. They allshow a good deal of round- 
ing and smoothing and occasionally of polish. Low mounds 
of gravel and other alluvium are to be seen in the vicinity, 
and similar accumulations may be observed in the broad 
flat valley north of the limestone belt. There is little 
doubt that these gravels belong to Rock Flat Creek or an 
ancestor of it; their presence at a distance of three-quarters 
of a mile west from the present bed of the creek, and at 
least 100 feet higher, would indicate a good deal of migra- 
tion and erosion on the part of the creek since their depo- 
sition. It is rather puzzling to find these gravels, and 
especially the boulders of three-foot diameter, on the highest 
point of the ridge separating Middle Flat from Rock Flat 
Oreek. I was at first inclined to ascribe their presence to 
ice-transport, but doubtless they are fluviatile deposits. 
Three well-formed crescent-shaped alluvial terraces 
mark the point near Pearman’s Hill where with a sharp 
S-bend the Murrumbidgee emerges from the Berridale fault- 
block. The highest is at 130 feet, and the others at 50 and 
25 feet respectively, above the present level of the stream. 
These terraces are of gravel principally, but the middle one 
is mostly mud. 
Molian deposits.—A noticeable feature of the Sydney 
road between Cooma and Bredbo is the great extent of 
country partially or wholly covered with drifting sand. 
Shortly after the road crosses Umaralla River, this sandy 
country begins, and it continues to within 5 or 6 miles of 
Bredbo. This mantle of sand gives the region a barren and 
