5 
morphic and granite country, similar to that near lloolcoomatta and its neighborhood, galena lodes are found, 
striking E. and AV.N.W., -with dips of from 20 to 35°, which will probably continue westward in that direction. 
Tlie geology of this part of the country i.s rather complicated, the rocks having been throum into nume¬ 
rous anticlinal and synclinal undulations, which have, in all probability, been accompanied by faults and 
dislocations, and require a detailed examination, before the stratification can be properly understood, for a 
considerable distance across the strike of these rocks, and otliers forming the Flinders Range, during which it 
is to be expected that fossils will be found whereby their geological horizon can be fixed. 
The following is a general list of the rocks referred to in this report, in descending order, with their 
ages provisionally : — 
1. Tertiary. —Sand, clay, gravel, and conglomerate ; gypsum and rock salt. 
2. Cretaceous. — Table-land formation, sandstones, kaolin, grit, and conglomerate; clay and sandy 
beds with gypsum, ironstones, sandstones, limestones, and calcareous clays in horizontal beds. 
3. Devonian C?J- —CIa)'-stones and conglomerates skirting the Flinders Range and elsewhere. 
4. Silurian f?)- —Limestones, elaj'-slates and shales, quartzites, calcareous slates, sandstones, sili- 
cious and conglomeratic limestones. 
5. Metamorphic. —Clay-slates, mica slate, and schists with granite dykes. 
6. Granite and greenstone. 
SrniNGS. 
The Mulligan Sjjrings are situated near the northern end of Lake Frome, some twenty miles to the east 
of the Flinders Range, in the Cretaceous formation. Two wells, some 6ft. or 8ft. deep, lie close together, the 
water slightly overflowing at the surface. There are low mounds of fine and coarse sand and silicious and 
calcareous rock close by, and outliers of table-hill formation in the neighborhood. These table-hills are com¬ 
posed of the usual yellow flinty quartzite, which here is devoid of any appearance of sand grains, and contains 
cavities coated with hj'alitc and other 0 ])alline coatings. Along the escarpment of one of these table-hills there 
are rounded, partially concentric nodules of ferruginous quartzite, with hyalite, calcedony, and traces of opal 
in the cavities. These sj^rings are similar in geological position to the nnid springs of the llarling and War- 
rego rivers; they are natural artesian wells, and indicate the pressure of subterranean water, which is trying 
to force its way to the surface. 
Blanvheioater Springs .—In the vicinity of Rlanchewater station, near Lake Blanche, there arc sevei'al 
sets of Rowing springs, also in the Cretaceous clay formation. Willow Hill Spring rises out of black jieaty 
ground, with deposits of calcareous tufa and iron ore and limestone, surrounded by soft cretaceous clay 
plains, with ridges of yellow flinty quartzite. 
Within a mile or two lie another set of sjirings, occupying an area of .several acres, and consisting of 
fresh, salt, and bitter water—all occurring over the same area, and often within a few j-ards of one another. 
A deej) gully near shows a section of undulating and horizontal beds of sandy clay, calcareous sandstone, and 
gypsum laj’crs, capped by gravel. The water lies on a level with, and is banked up a little above, the .sur¬ 
face, the ground in the neighborhood being of the nature of a bog—in some places covered with vegeta¬ 
tion, in others coated with a white efflorescence, an anal 3 ’sis of which has shown to contain an unu.sual 
amount of alkaline carbonates. 
St. .Mary's Pool. —In the bed of the MacDonnell Creek is also a flowing spring, in similar forma¬ 
tion, below escarpments of the same quartzite or i)orcelainised rock which is generally found capping the 
table hills. 
On some of the hard blocks of quartzite and quartzose sandstone near this place there arc marks some¬ 
what resembling the impressions of the feet of human beings, kangaroo, birds, kc., which are considered to 
be fossil tracks. On examination the}' appear to be mereh' rough imitations of such, the smooth surface of 
the rock having been removed by some hard instrument to a slight depth, the pitted marks of such action 
beiii'^ plaiiil}' visible. Be.sides this, in one case, the plane of the supj)oscd impression is at an angle with the 
planes of bedding of the rock. 
Evidences of Extinct Springs. —Between Mulligan and Blanehcwater, at several points, in groups rising 
in small, roughlv dome-shaped masses above the surface of the soft claj' of the plains, are semi-concentric 
masses of iron ore (hematite), which are doubtless the remains of old spring deposits. In the same neigh¬ 
borhood similar shaj)ed circular protuberances of limestone come to the surface, which I take to be also the 
old outlets of e.xtinct calcareous sjirings. The surface of the ground over a largo extent of countiy here is 
covered with jiieces of gravel of iron ore, in addition to nugget-like jiieces of jiorcelainiscd rock, from which 
circumstance tlie watercourse flowing through it is called Drearj’ Creek. In the sections shown in some of 
the creek banks bands of ferruginous claj'stono and ironstone are found, as well as ferruginous conglomerate. 
As jjrcvioush' shown, water i.s rather jilentiful in the older rock formations, allhougR it cannot bo deter¬ 
mined before sinking whether it will be brackish or fresh. The numerous beds of limestone which are 
interstratified with the other rocks arc, as mentioned above, favorable to the storage of water in caves and 
hollows and undergi'ound streams. The occuiTcnce of calcareous conglomerate and tufa on the surface of 
the older rocks, and in gullies and creeks traversing them, points to the enaption of water charged with lime 
at some not verj' remote period. The Flinders and other ranges Ij'ing to the south of the jdain and sandhill 
country act as a dam to prevent the subterranean water from reaching the sea ; this gives rise to the natural 
artesian sjjrings, such as Mulligan, Blanehcwater, &c., &c. This area is colored green on the map. The 
natural artesian wells show that in those localities water will rise to the surface when the water-bearing 
strata have been jnerced. Whether it will do so all over the area above mentioned depends on the level of 
the land, the depth of the formation, the undulations of the bed rock, &c. It is, however, cerUiin enough 
that water will be found in sufficient (juantities by sinking to a moderate depth. By tubing back the salt 
water met with in sinking, a bore maj' bo carried down—a.s the strata .are horizontal—from one stratum 
through into another, u-itli the certainty of getting water of a different quality. I believe that the lowest 
bed underlying the i)lains, from my present observations, is a boulder conglomerate and gravel, and that 
limestone rock's underlie this over a considerable part of the area, both of which things are in favor of there 
bein'' vast supplies of underground water. Besides the water to be obtained beneath the lowest beds, other 
vvatms may be met with at shallow depths, such as in watercourses and holes which have been filled up with 
sand or other material. The deep subterranean water maj' also be expected sometimes in a porous stratum 
near the surface, into which it has been forced by the pressure of gravitation, gas, or steam. 
August 1st, 1883. HENRY Y. L. BROWN, Government Geologist. 
PLANS 
B_No. 146. 
