Excursion to Belvoir. Thursday, September 17th, 1908 - Geologists' Association excursion

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Step faults in Middle Lias Limestone at Harby. BGS image P805313.
Step faults in Middle Lias Limestone at Harby. BGS image P805314.

Excursion to Belvoir. Thursday, September 17th, 1908. (Transcription of GA Circular No. 99. Session 1907–1908.

DIRECTORS : Lieut. G. E. COKE, R.N., F.G.S., and H. PRESTON, F.G.S.

EXCURSION SECRETARY : T. W. READER, 17, Gloucester Road, Finsbury Park, N.

Leave St. Pancras 10.6 for Leicester, taking excursion tickets, 6s. each. Arrive Leicester (Midland) 12.14. Take tram to G.N. station. Leave by 12.40 train to Harby, taking cheap return ticket, 1s. 9d. each.

Members intending to take part in this Excursion are requested to send their names in to Mr. Reader so that arrangements can be made for driving.

Conveyances will meet the party at Harby and Stathern station at 1.40 p.m., and convey them to the Eastwell Ironstone mines.

The first part of the journey is in a south-easterly direction over Lower Lias clay, and in front are the irregular and picturesque hills of Middle Lias rising to an elevation of over soo ft. above sea level.

The principal workings to be visited are near "White Lodge," where fine sections of Ironstone (Middle Lias Marlstone) are exhibited. The quarry face runs W.S.W. to E.N.E., and about half-way down the face a fault is seen having a down-throw to the east of 6 ft., with smaller faults beyond. At the east end of the section there are a series of twelve or more step faults which, within a distance of 60 yards, drop the beds about 14 ft.

The upper section at the east end shows overthrust of Boulder Clay on Upper Lias (paper shales), the Boulder Clay varying in thickness up to 10 ft. The thrust-planes, which rise rapidly from the east, form a number of thin beds (4 to 6 in. thick), of gravelly marl interstratified with Lias Clay.

Where the Ironstone finally dips under the clay there are 10 ft. 3 in. of good Ironstone overlaid by 20 ft. of clay, and the probability is that a strong fault occurs immediately beyond the end of quarry, which has brought the top beds of Upper Lias (Leda ovum beds) into juxtaposition with the Marlstone.

The worked Ironstone has a variable thickness up to 13 ft., below which is the blue and green-hearted stone of inferior quality. The Ironstone is sent to the Midland furnaces, where it is used largely as a flux with other ores. Arrangements will be made for tea. Cost of drive about 1s. 6d.

Return train, Harby to Leicester, 6.25, arriving Leicester, 7.25.Return train from Leicester to London 9.28, arriving St. Pancras, 11.13 p.m.

During the wait at Leicester visit the Public Museum, which is close to the Midland Station.

REFERENCES.

Geological Memoir and Map, S.W. Lincolnshire, sheet 70.

WILSON.—"Lias Marlstone of Leicestershire as a Source of Ironstone." Midland Naturalist, vol. viii, 1885.

List of photographs

Page 55 P805313 Step faults in Middle Lias Limestone at Harby. Excursion to Belvoir, September 17th 1908. In a distance of about 60 yards some 12 or more faults are seen, all hading towards the east and varying in throw from a few inches up to 2 ft 9 in, the total sum of the faults dropping the beds about 14 ft. These step faults being the forerunners of a large fault which brings the top beds of the Upper Lias in juxtaposition with the marlstone.
Page 55 P805314 Step faults in Middle Lias Limestone at Harby. Excursion to Belvoir, September 17th 1908. In a distance of about 60 yards some 12 or more faults are seen, all hading towards the east and varying in throw from a few inches up to 2 ft 9 in, the total sum of the faults dropping the beds about 14 ft. These step faults being the forerunners of a large fault which brings the top beds of the Upper Lias in juxtaposition with the marlstone.