108

REPORT OF AN EXCURSION TO SU NDE R LA ND AND .

WHITSUNTlDE, MAY 24TH TO 30TH, 1912. By DAVID WOOLACOTT, D.Sc., F. G.S., D irector of the E x cursion. T HE members of the Association arrived in Newcastle on Fr iday evening, May 24th. T he head quart ers of the party was at th e Gra nd H otel, Percy Street. Mr. A. H. Williams acted as Excursion Secretary. The writer acted as Dir ector throughout the excursion, but several local geologists, including Miss Heslop, Dr. Smythe and Mr. S. R. H aselhurst, att end ed on certain of th e da ys and assisted in elucidating parts of th e geology of th e district. The weath er throughout th e five days was fine and clear, and very suitable for geological work. SATURDAY, MAY 25TH. T he mem bers left by th e 9.20 a.rn, train for , an d after walking north th rough th e fields for two miles descended to the coast north of H artley. The coast-line between here and Ty nemouth- to which place th e party proce eded-some seven miles to the south, affords excellent expos ures of the Middle .Coal Measures an d of the lower divisions of the Permian rocks. The Coal Measures are, along the whole of th is par t of th e coas t, highly faulted by a series of east and west dislocations, and some of th e exposures of these are very clear and interesting. The party examined several faults between Collywell Bay and Whitley in the morning, and were much intereste d in th e details of som e of them, such as "leaders," " step faults," " faults cutting one an oth er," etc. T he position of th e small outlier of Yellow Sands that occurs at the top of the cliff in Collywell Bay was shown. I t is th e most northerly patc h of Permian exposed in Nor thumberland. T he Collywell Dyke, which comes to a head in the middle of Collywell Bay, and has metamorphosed the shale at its side, was examined in detail. A shale, with " cone-in-cone " structure developed in it, exposed on the foreshore ju st nort h of St. Mary's Island, proved of considerable interest to some mem bers of the party, an d an interesti ng discussion took place on the cause of thi s stru cture. Dr. Evans regarded it as a concretionary structure, and looked upon it as being produced in a calcareous shale by the coming together of the carbonate of lime, but others thought it might be a produ ct of pressure only . This particular shale is more calcareous in the par ts in which "cone-in·cone " structure is developed. After lun ch some time was spent in a detailed examination of the thrust an d unconformity at Whitley described l'ROC. GEOr.. Assoc., VOL. XXIV. PLATE 24.

[FllOto b" T. W. Reader. [['ltolo by T. W. Reader. A.- THE COLLEYWELL DYKE, COLLEYWELL BAY. B.~THRlJSTAT WHITLEY.

To face page 108. EXCURSION TO AND TYNEMOUTH. 109 by Professor Lebour and Dr. Smythe (Quart. '}ourn. Geol. Soc., vol. xli, 1906, p. 530). The peculiar disturbance here produced by the horizontal movement of a thick, compact sandstone over beds of shale, sandy shale, and a mussel­ band, proved of special interest, and while all admitted the evidence for the thrust, some seemed to regard that for the unconformity as rather doubtful. They looked upon the "pebble bed" lying above the disturbed plane as a crush conglomerate, but admitted that they had not had time to examine the section thoroughly. The writer considers the evidence for both the thrust and unconformity is quite satisfactory. The party then examined the"megascopic pseudo-stromatism" which has been developed in some sandstones by thrusting, in the bay to the south of the Table Rocks. This exposure had first been noticed by Mr. S. R. Haselhurst a few months before (Proc. Univ. Durham Phil. Soc., vol. iv, pt. 3, p. 162), and after he had described it to the members of the Association, they admitted that the explanation given by him seemed to be the correct one. In the next bay, Bay, the Yellow Sands, Marl Slate, and the lower divisions of the Magnesian Limestone were seen resting unconformably on the Coal Measures in the north of the bay, and also faulted against them by the Ninety Fathom " Dyke" in the south. The rounded grains composing the Yellow Sands, and the irregular way in which they are cemented, were clearly seen here. The cemented fissures in the Yellow Sands proved of interest, and the writer and Mr. Haselhurst showed that there were two sets, and that one set had faulted the other. It was also shown that the Permian strata in the bay lay in the form of a dome, possibly owing to the thrusting of them against the Coal Measures on the other side of the Ninety Fathom Dyke. The party now proceeded southwards to Tynemouth, where the splendid section showing the lower divisions of the Permian resting on the Coal Measures was carefully examined. Here the breccias of the Middle Permian are seen on the top of the cliff, but as they are much better exposed on the south side of the Tyne in Frenchman's Bay, about two miles to the south, and as it was proposed to visit this section on Monday, the discussion was postponed until that day. The beds exposed on Tynemouth Cliff are:- ft. r. Brecciated Beds (Middle Magnesian Limestone), Breccia and" Negative" Breccia ...... 18-20 2. Disturbed Upper Beds of Lower Magnesian Limestone . 5 3. An Arenaceous Limestone (Lower Limestone) passing into alternations of Marls, Limestones and Sandstones 12-18 4. Marl Slate .... 3 S. Yellow Sands, variable in thickness 5-40 U nconforrnity, 6. Red Beds of Coal Measures 3° Iro DAVID WOOLACOTT,

The party now returned to Newcastle, where they arrived about 6.30 p.m.

MONDAY, MAY 27TH. On Monday the party left Newcastle at 9-47 for East Boldon. From here they walked across Boldon Flats towards , the first part of the journey being over boulder-clay. Just before entering Cleadon the exposures of sand and gravel in the sand­ pits were examined. These current-bedded sands and gravels contain marine shells, and occur at a level of 100 ft. above sea­ level. They are generally regarded as a raised sea-beach, and most members of the Association seemed to agree with this inter­ pretation. The party then proceeded to the magnesian lime­ stone escarpment on Cleadon Hills, where some minutely con­ cretionary fossiliferous limestone belonging to the Upper Lime­ tones was examined. Here Mr. A. B. E. Blackburn, engineer to the Sunderland and Water Company, kindly invited the party to inspect the Cleadon Water Works and to ascend the tower at these works, from the top of which a fine view of the country was obtained, and the writer pointed out the chief geographical and geological features observable. The thanks of the party were accorded to Mr. Blackburn for his kindness. The journey was continued across Cleadon Hills to Marsden Quarries, where the bed of gravel and sand was again seen, and excellent sections of the Upper Concretionary Lime­ stone examined.* The various forms assumed by the concretions in these rocks proved of great interest to most of the members, several of whom had never seen this rock in the field before. Several Upper Limestone fossils were obtained-PleuropllOrus costatus, Myalinil ha1tSlllil1tlli, etc. The writer showed that the beds were divisible into three types, viz., "bluestones," containing a very small percentage of magnesium carbonate and never concretionary; "greystones," containing a varying percentage of magnesium carbonate (from about 4 or 5 to 30 per cent.) and generally concretionary; and "marls," soft pulverulent limestones, containing a high percentage of mag­ nesium carbonate (40 per cent.) and never concretionary. He also showed that for field purposes the concretions might be divided into cellular and spherical. The concretions were always more calcareous than the cementing matrix, and the concretions had been produced by the coming together of the calcium carbonate around points, along lines, etc. Dr. Evans thought that if the rock contained gypsum the removal of it might have something to do with bringing the rock into a condition suitable for the setting up of the molecular forces that had brought about the concretionary structures. The party now proceeded to * The Harton Coal Company kindly allowed the members of the Association to visit these qnarries. PROC. GEOL. Assoc., VOL. XXIV. PLATE 25.

[Pltoto b)' T. W. Reader.

A.-CINDER COAL. SECTION AT HIGHT ANGLES TO DYKE, COALEY HILL.

[Pltoto b)' 1'. W. Reader.

B.-MARSDEN ROCK, MARSDEN BAY.

To face ptlge 110, EXCURSION TO SUNDERLAND AND TYNEMOUTH. l l I

Marsden Bay, passing along a most rugged coast, with numerous stacks, detached rocks and arches. After lunch they examined the section between Marsden and South Shields. This section has been fully described by the writer in a paper entitled" A case of thrust and crush-brecciation in the Magnesian Limestone, " (Univ. ofDurham Phil. Soc., Memoir No. I). It affords proof that one of the ways in which the Brecciated Beds that form so characteristic a feature of the Magnesian Limestone in the north of Durham County were produced was by the action of more or less horizontally-directed forces, i.e., by thrusting. The party examined this section thoroughly, and it was generally admitted that the crushing and brecciation of the beds had been brought about by the action of a thrust. Professor Lebour, Dr. Evans, C. T. Trechmann, and other geologists, have suggested that the removal of beds of limestone or gypsum may have produced brecciation in the magnesian limestone; and in places this may be so, but the phenomena here necessitate the action of a powerful thrust for their explanation The beds are folded, cleaved and brecciated by crushing in Marsden Bay, and disturbed along a thrust plane in Frenchman's Bay. The whole of the divisions of the Permian can be examined along the coast between Marsden Quarries and Frenchman's Bay. The strata are: ft. Upper Concretionary Limestone too Flexible Limestone. •.... 10 Middle Yellow-bedded Limestone (Marsden Bay) roo Middle Brecciated Beds. ...." 60 Lower Regularly-bedded Limestone of Frenchman's Bay 40 Marl Slate " 3 Yellow Sands (base not seen) 3 From Frenchman's Bay the members proceeded to South Shields and took train back to Newcastle, reaching the latter place about 6.30 p.m.

TUESDAY, MAY 28TH. The party left Newcastle by the 9. 17 train for Sunderland. They proceeded by tram to Kayll Road and then walked to . The lower divisions of the Permian are exposed here along a bold escarpment. The beds exposed are the Yellow Sands, Marl Slate, Lower bedded limestones and the Fossiliferous Limestone. The section is peculiar as the two middle divisions are missing from the east end of the section. There is evidence of horizontal movement here in the grooving of the base of the Fossiliferous Limestone, the slickensided planes in the Marl Slate, and the disturbed beds in the railway cutting behind the escarpment. In a small quarry a little to the south some consider­ able time was spent collecting fossils from the Middle Fossiliferous lIZ DAVID WOOLACOTT,

Limestone. Here a soft, yellow, highly-magnesian limestone is almost entirely formed of casts of animal life that existed in the Permian Sea. Productus horridus, Fenestella retiformis, Spirifer alatus, Camaraphoria schlotheimi, and numerous other fossils were collected. Conveyances now met the party and took them to the Kaim at Grindon. This high mound of gravel and sand, standing isolated, and deeply excavated for sand, proved of con­ siderable interest. A large number of rocks "foreign" to the district (Lake District, Cheviots, etc.) were collected in a short time. The drive was continued into Durham Road to Humble­ don Hill, where the Fossiliferous Limestone is exposed. The old quarry here was one of the early collecting grounds of King, Howse, etc. Mr. A. B. E. Blackburn kindly invited the mem­ bers to lunch, which was thoroughly enjoyed after the hard work of the morning. Dr. Evans and Mr. Whitaker expressed the thanks of the Association to Mr. Blackburn for his kindness. After the Humbledon Hill Water Works and section had been examined the party proceeded to Tunstall Hill. Here the great thickness of unbedded Fossiliferous Limestone was examined, and the writer showed that it appeared to be part of a long shell-bank, and that the peculiar contour of the country was largely due to this bank having withstood denudation while the rocks on either side had been removed. The journey was now continued through to the coast, along which a most pleasant afternoon was spent, the work forming a pleasant contrast to the inland work of the morning. From Ryhope to Sunderland the section is at first composed of Middle Magnesian Limestone capped by boulder-clay and glacial sands. The most interesting feature is the mass of slickensided breccia known as Jean Jiveson's Rocks, which appears to be a breccia forced up from the beds beneath-" intruded breccia." Farther south nearer Sunderland the Middle Limestone is thrust over the Upper Limestone, and along the thrust plane the Middle Lime­ stone has been sheared, a "phacoidal structure" being developed in it, and it has also been fractured into large irregular blocks­ "block fractured." From here southwards the Flexible Limestones and Upper Concretionary Limestones were examined. This part of the section is described in detail by the writer in his paper on "The Stratigraphy and Tectonics of the Permian of Durham (Northern Area)" (Proc. Uniu. of Durham Phil. Soc., vol. iv, pt. 5, fig. 10). The party now proceeded to Sunderland, and left for Newcastle about 5.30.

WEDNESDAY, MAY 29TH. The party arrived in Sunderland from Newcastle about 9.45, and at once proceeded to Seaside Lane, . They imme­ diately proceeded to the Submerged Forest, which was fortunately P ROC. GEOL. Assoc., V OL . XXIV. PLATE 26.

[Phot o by T. lV. R eader .

A.- CELLULAR CONCRETION , F ULWEL L Q UARRI ES, S UNDERLA ND.

[Phot o by T. lV. R eader.

B.-SPHEIO CA L CONCRE TlO:-lS, F ULWELL Q UA RRI ES, S U N DE RLAND.

To f ace page II2 . EXCURSION TO SUNDERLAND AND TYNEMOUTH. 113 very well exposed. This is a peat-like formation, with tree roots t"n situ, remains of trees, leaves and nuts resting on boulder-clay, and occurring between tide marks. It is often covered up for years, but was specially clear on this occasion. Alter examining this deposit they proceeded south to Parson's Rock, where the concretionary limestone is very well exposed in one of its characteristic forms-the cannon-ball. The large and regular size of the concretions, and the radiating structure commonly occurring in them here, were matters of interest to the party. This bed dips south, and is succeeded by about 100 ft. of the uppermost division of the Magnesian Limestone in the north of Durham County. It is a regularly-bedded yellow magnesian limestone, sometimes compact, but often minutely cellular, being composed of minute hollow spheres. It has been excavated into a series of caverns at Holey Rock. The party now left the coast, and walked inland for about two miles to Fulwell Quarries, which Mr. James, the manager, had kindly allowed the Association to visit. In this quarry the concretionary limestone reaches its most characteristic development. The varied forms-cannon­ ball, honeycomb, coralloid, rod-like, etc.-are here better developed than in any other exposure. The Director pointed out that it was in this quarry that Dr. Abbott had studied the concretionary limestones, and that a large number of his best photographs were from the rocks here. Nearly 100 ft. of con­ cretionary limestone, capped by boulder-clay, occurs. There are at present two typical types of rock exposed-cellular greystones and so-called "marl." (See description of Tuesday's visit to Marsden.) Invertebrate fossils are never found associated with the concretions in this quarry, although they do occur at Marsden. Fish remains (Acentrophorus) are of fairly common occurrence in a fish bed, and in the beds immediately above it. Some brecciated masses of concretionary limestone were examined in the Southwick Quarry. The beds of sand and gravel (referred to in description of Tuesday's work) were again examined here, resting at a level of 1 SO ft. After some considerable time had been spent examining, photographing and discussing the various features of this pecu­ liarly interesting rock, most of the members proceeded to Sunderland Museum, where the local exhibits of geological and archeeological interest were examined. Two informal excursions were held during the week. One of them, which was attended by about a dozen members of the party, was through the district lying immediately to the north and west of Newcastle. The party first proceeded to , and examined the "wash out " in the Coal Measures at this place. From there they walked on to Kenton, where the Grind­ stone Sill is exposed. This is one of the best exposures of the sandstones from which the famous Newcastle grindstones are made. PROC. GEOL. Assoc., VOL. XXIV, PART 2, 1913.J 9 114 EX CUR SIOX TO SUNDERLAXIJ AND TY:O:~ O l;TH.

Boulder-clay covers the sandstone, and numerous Lake District, Cheviot an d other " foreign " boulders were seen. Dr. Smythe pointed out that the surface of the sandstone is a " Roches moutonnee," The party now pro ceeded to Newbiggin Dene, where th ey had an opportunity of examining a glacier-lake over­ flow channel. Dr. Smythe describ ed th e glacial geology of the district and the mann er in which the system of glacier lakes and overflow channels were produced in this district. From here the party proceeded to Coaley Hill, where there is a most interesting exposure of a dyk e a bout 30 ft. wide, which has metamorphosed a coa l seam , turning it into a cinder coal with a prismatic structure. The dyke had also at that time a fissure filled with highly decomposed material down th e middle of it. The journey was continued from here past the Ka irn at Dewley Hill to Callerton, where the train was taken to Newcastle. Another in formal excursion, which two or three members attended, was mad e to the Boldon Colliery, which the man ager kindly allowed them to visit. On T uesday the members of the Associa tio n dined in the Grand H otel, Newcastle, and kindly invited Miss Heslop, the Director, and Dr. Smythe to meet th em. After dinner the Preside nt, Dr. Eva ns, conveyed the thanks of th e Assoc iation to the Director for his kindness during the visit of th e Association to Newcast le. PLATE 27. PROC. GEOL. Assoc., VOL. XXIV.

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FIG 3.-SECTION ACROSS THE PERMIAN OUTCROP FROM HIGH DOWNS QUARRY. HETTON, TO SUNDERI.AND.-D. Wooiacott.

To face page '14. PROC. GEOL. Assoc., VOL. XXIV. PLATE 28. SE NW Marsden Bay Velvet Man TROW ROC I<.S 'Beds Haven BRE OCIA T ED, FOLDED, AND FISSURED AREA...... ~r'.j"! ·",nl'r"'_ '2. 1. ~ SectL.on B t!low ~5 4- 2- 3 43

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