H.—34.

In the Coal Creek area a sharp asymmetrical syncline, broken by the important Saddle Fault, separates the eastern anticline from the broad dip-slopes of Mount Davy. The Saddle Fault, actually a group of closely spaced faults, is analogous to the Spring Creek zone, but on a smaller scale. It was not picked up in Batty Creek, but appears a little to the east of Trig. MM, crosses Coal Creek near the junction with Coulthard Creek, and apparently passes obliquely across the Seven-mile - Coal Creek divide, thence across Davy Creek, and forms the eastern boundary of the Liverpool Mine block. North of Davy Creek the broad west-dipping monocline referred to earlier terminates, and east of the Liverpool block the country is faulted and closely folded as far as the north-east corner of the coalfield. A fault with a downthrow to the west, of the order of 200 ft., crosses the south-west spur of Mount Davy and Davy Creek, but has not been identified farther to the north-east. Southward it must rapidly die out between Herd and Coulthard creeks. North-western Area. The most notable structure of this area is an open syncline approximately 50 chains wide which passes through the central part of the Strongman State Mine workings and strikes about due north. This structure is well established from observations taken in the mine workings and from outcrops in Nine-mile Stream, in Griffiths Creek, and to a less extent from outcrops on the south side of Ten-mile Valley. It is noteworthy that this structure differs in trend from the main faulting system of the field which strikes approximately between 25° and 30° east of north. The smaller short folds that occur sporadically through the area approximate more nearly the strike of the faulting system. The north-easterly-striking fault system is the most consistent structural feature in this area. The faults have been traced from Ten-mile Stream southwards to Kiwi Creek, and in general decrease in throw in this direction. On the other hand, the Transformer Fault, where it cuts off the James seam south of Cannell Creek, has increased its throw. It is possible that this fault, and others of this area, do not persist as single fractures, but that they are distributed by subparallel displacements. Faults transverse to the main system are of a much smaller order, but are important in mining operations and therefore have received considerable attention. " Splits" from main faults are occasionally encountered, many having considerable throw and diverging at a low angle so as to be difficult to distinguish underground from the principal fault. An example is the "90 ft. Fault " which intersects the main drive of the Strongman State Mine about 26 chains from the entrance. It appears to join the Armstrong Fault a few hundred feet north, whereas to the south both faults die out very rapidly and appear to be represented across Kiwi Creek merely by minor folding of the strata. The evidence so far collected shows that compressional faulting is subordinate to tensional. In the absence of key beds it is not always possible to determine the type of fault. The supposedly greater crushing of strata adjacent to compressional faults is not reliable evidence of compressional faulting in the strata of the Grey coalfield, for folding of incompetent beds between competent ones, as demonstrated in a small outcrop or in mine workings, though perhaps suggestive of compressional faulting, may result from normal faulting. Coast Faults.—Along the coast between Nine-mile and Ten-mile creeks there is a series of normal faults, generally striking north-east, with westerly downthrow. One example is to be seen on the west side of the main-road bridge crossing the Nine-mile Stream. Another crosses the main road just after it turns east into Ten-mile Valley, showing the Island Sandstone downfaulted to the west of the Brunner Conglomerate. Fred Fault.- This fault has a north-west dip of approximately 70°. It enters the area at Fauth and party Mine in the Ten-mile valley and cuts off these workings on the west side. Traversing the east side of Moors and party workings in the James seam, it crosses the Strongman Mine Koad 40 chains from the coast, where the Island Sandstone is again seen downfaulted against Brunner Conglomerate. Southward, it forms the western boundary of the James State Mine, the throw being estimated at probably over 100 ft. Griffiths Greek Fault.—This fault is first definitely traceable where the Strongman Mine Road crosses Griffiths Creek, Island Sandstone being downthrown to the west of Brunner Conglomerate. This fault, or a related fracture, cuts off the James State Mine workings to the east. A 1 Fault. —This fault is deduced from stratigraphic evidence in Ten-mile Valley, where it appears to displace the coal seams to the extent of 150 ft. It is next to be observed crossing Griffiths Creek, where it is apparently dying out, as it is not seen displacing the Brunner Conglomerates which cap the ridge to the south. However, about 3 chains east of this point where it should cross the ridge, there is another fault which may have replaced the A 1 Fault, though it is indicated only by fractures in Griffiths Creek. It crosses Nine-mile Stream in the vicinity of the road bridge about 20 chains west of the mine entrance. Hunter Fault. —This is not well established, but the mapping suggests that a mudstone stratum and a coal-seam have been displaced about 300 ft. The fault appears to be of no great length, for it does not occur on the ridge south of the Ten-mile Stream. Transformer Fault.—With a westward downthrow of about 300 ft., this fault cuts off the Hunter and party seam to the east and the Armstrong and party (Strongman State Mine) seams to the west. A change of vegetation on the crest of the ridge south of the Ten-mile valley may indicate its approximate place. It is to be seen on the ridge south of Griffiths Creek, where the Brunner Conglomerate is downthrown against the underlying sandstones ; thence it crosses the main drive of the State Mine near the entrance. On the ridge east of Trig. GG, the Brunner Conglomerate is downthrown to the west of the sandstones. South-westwards, across the headwaters of Cannell Creek, the displacement of the James seam is tentatively given as 500 ft. Contrary to the general rule in the area, the throw on this fault is greater to the south than to the north. It is possible that, like others in the field, it may die out and its displacement be taken up by other nearby faults.

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