Separate folded sheet: "Lapphullet, Nord - Rana, Norway."
Surveyed by Cambridge University Caving Club (and after Horn, 1934)
CRG Grade 4: Drawn by Oliver C. Wells.
These notes refer to a caving expedition to Northern Norway, organised by the Cambridge University Caving Club in August and September, 1956. The members of the expedition were M.Duerden, I.P.Dyson, R.J.Kirkland, J.D.Morris, W.J.Spowage, W.F.Theakstone and O.C.Wells; and visits were made into the three caves, Larshullet, Lapphullet and Olavsgrotten. These notes contain the results of our explorations, including the descent of the 117 ft. pitch and some survey work. In addition, many photographs were taken. These three caves occur together in rather older, metamorphosed limestone, (Cambro-Silurian age) containing considerable quantities of mica-schist inclusions. In all, more than twenty trips were carried out, and this was made possible by the choice of a camp site some distance from the road by the side of Lake Reingardislivatnet.
The purely sporting aspects of the expedition have already been described (1) and a note about sumps has also been published (2). The area has been described in English by Railton (3), who recounted an expedition made in July and August, 1951. In particular, Railton describes the exploration he carried out to the lowest point in Larshullet and he discusses the formation of this cave. The 'classic' account of the area was published by Horn (4), who spent seven years studying the geology and caves of the area. Horn's work contains cave surveys and surface plans and the present work is based to a large extent on the surveys he published on pages 45, 46, 47 and 51 of his paper. Unfortunately, none of the party was able to read Norwegian and much time was spent on Horn's text with a pocket dictionary. Since our return, Kirkland and Theakstone have been studying the remaining literature on Norwegian caves and in particular, Holmsen's work (5), describing the geology and distribution of caves over the wider area of Rana. We were fortunate in having at our camp site copies of both Railton's and Horn's works.
On the first day, parties visited Olavsgrotten and Lapphullet. Olavsgrotten was found to be much as described by Horn, and we will say no more except that this cave ends in a sump which will be referred to again later. In Lapphullet the situation was quite different and we found ourselves on new ground almost at once. Horn's survey is very incomplete, and in fact, the cave extends about twice as far as he shows. Most of the passages had, however, been explored since Horn's time and on our first visit we discovered the direct route out of the cave by following the increasingly evident trail of debris left by previous visitors. Those extensions bring Lapphullet much closer to Larshullet and it was decided to carry out a Grade 4 survey.
In Larshullet advances were also made. Two parties descended Railton's pitch (76 ft.) to discover that the sump described by him had drained, leaving a gravel soakaway, presumably due to the reduced flow of water during our visit. This observation adds weight to Railton's suggestion about a constricted outflow at the bottom of the cave. He also describes the entrances of some unexplored passages, but we were not able to explore these to our satisfaction and further trips are needed. The Sørgangen (South Passage) in Larshullet was found to end in a sand choke at the point shown on Horn's survey. We excavated this choke to discover a few yards of a more rapidly descending passage leading to a second sand choke which defied our efforts at digging. Working conditions are good, but it would be a long job. The sand is much cleaner than that in Lapphullet. The cross-section of the Sørgangen was found to be rather more complicated than shown in Horn's survey and at several places, parallel bedding-plane passages or tubes can be entered. At one point, in one of these, it is possible to hear the sound of running water (in a cross passage) which is probably the stream in the Nordgangen (North Passage) not far away. At another place, a small hole among boulders can be entered to the top of an 18 ft. pitch which was descended, but it was found to connect with the Nordgangen as shown on Horn's survey (by the "lste avsats").
Our greatest exploration was the descent of the 117 ft. pitch in Larshullet, Gunnar Horn marks the top of this pitch on his survey, at a point some 150 metres from the entrance (on the south side of the main passageway) and remarks in his text that it might lead to new passages. It is not possible to plumb the depth of this pitch because of the rock ledges which nearly touch the ladder at several points, and during the initial descent, increasing amounts of ladder were paid out while Dyson sheltered on the various ledges. This situation is not without its dangers, and during the withdrawal of the tackle (which is difficult), a very large boulder fell from near the top and we were very fortunate to escape without a serious accident. Two descents were made of this pitch, under the cross-examination of the surveyor who, from the top of the pitch, noted down in his book information relayed by the explorers; and it is from these details that the section was drawn. The whole pitch lies in a cross rift and there is no way on except possibly right at the top on the other side, and this would appear to be quite inaccessible. The bottom rung of the ladder rested on a sandbank with a large pool of water a couple of feet away. Failing an accurate survey, we estimated the level of the sump as best we could, and our figure was then found to agree, within three metres, with the estimate given by Horn of the sump in Olavsgrotten, and according to Horn's surface survey (page 43), these sumps are at a distance of less than 100 metres; possibly in the same cross rift or in a parallel one.
Horn's survey of Lapphullet was completed at Grade 4 standard, involving four survey trips. The extent of Horn's survey is shown, at a reduced scale, in a sub-panel. (See folded survey sheet). The compass used was a liquid-filled card type as issued to German wartime air crews and this is a type particularly suitable for use underground. The distances were measured with a knotted cord. (The use of knotted lighting flex gives a cord that has negligible stretch and which does not affect the compass). The lengths between knots were correct within one percent. Survey legs were marked out to be exact lengths of the cord to eliminate interpolation errors. It is convenient to have a reasonably short cord (six yards) and to mark the survey points on the tops of suitable boulders at exact lengths of the cord. (An additional cord of twice the length would have been useful in the large passages).
The only clinometer available was a high-class geological instrument which was hopeless for taking lines of sight. Fortunately, the roofs were mostly straight and accurate measurements could be made of the roof angle. Over most of the cave this was almost exactly twelve degrees, becoming smaller as the entrance is approached.
The traverses wore drawn up at large scale (1in. to 4ft.) on a drawing board and the coordinates of the completed traverses were measured in order to compute the misclosures and apply corrections. The first closure was along the toruous South Entrance Passage, compared with the survey as drawn by Gunnar Horn and the error was less than ten percent. In drawing the plan, Horn's value was taken as being correct. The other two closures were against our own work and both closed to better than five percent. The fair copy was drawn at a scale of 3 : 2,000 (approximately 1 in. to 56 ft.) in order to be reduced photographically to the same scale as used by Gunnar Horn (1 : 2,000). In drawing the fair copy, details were taken from the field notes and also from a preliminary drawing which had been made in Norway immediately after the surveying trips. The survey shows the closeness of Larshullet and Lapphullet and conveniently it was possible to show the position of the 117 ft pitch on the same map. Unfortunately, Horn did not publish a section of Larshullet and this section is therefore drawn in a diagrammatic manner. The horizontal distance was taken from Horn's plan, and the height was estimated by measuring roof angles and allowing for vertical drops. Other information, also, has been taken from Horn as acknowledged on the plan. This was principally in the entrance passages of both caves and in the relative positions of their entrances. Only the entrance passages of Larshullet have been included, because of the very great length of this cave (1Km.).
When drawing the plan the Low-Level Route has been omitted but its ends are indicated. Some of Horn's passage detail has been omitted. Metres have been used throughout the printed survey in order to conform with Horn's usage, thus for example, the 117 ft. pitch has become the 36 metre shaft. When drawing the section, the depth given by Horn for his part of Lapphullet was taken as correct. At the lower end of the cave, it was easy enough to follow the individual beds along the roof and to measure their angle at intervals, and this angle never varied by more than a degree or so. This became progressively more difficult as the entrance was approached and a certain amount of estimation of heights was involved. According to work published by Warburton (6), describing the surveying of Eastwater Cavern in the Mendip, the instrumentation used by us in this cave is likely to give an accurate plan with all the depths exaggerated by about twenty percent. In the present case, an effort was made to reduce this latter inaccuracy by the constant measuring of roof angles and by a reduction in estimated heights, but even so a careful check with an aneroid is still necessary.
During one of the survey trips, a bedding-plane was noted which was not pushed to its extreme and this is indicated by the question mark on the plan. As mentioned above, the fair copy was drawn out to a scale of 3 : 2,000 and dyeline prints are available of this size (30 in. by 18 in.) for field work.
After drawing the survey of Lapphullet, details of the nearby Larshullet were drawn in from Horn's work. It was found that the end of Lapphullet approached the bottom of the 117 ft. pitch quite closely, both in direction and level and the separation is given as being less than 50 yards. This level is also practically (if not exactly) the same as the levels of the Olavsgrotten sump and the floor of the big chamber in Larshullet as mentioned by Railton. The three caves would appear to be part of the same system. As a point of information, the end of Lapphullet was a large area of sand with the stream disappearing into a fissure which did not appear at all suitable for any form of attack.
We made an inconclusive attempt to prove a connection by placing three ounces of fluorescein in the stream at the end of Lapphullet and there was no sign of the dye when the 117 ft. pitch was descended twenty-four hours later. The stream in Larshullet, as far as the top of Railton's pitch was observed at both six hours and twenty hours later without success. Unfortunately, we did not descend Railton's pitch to examine the other stream at the bottom. No attempts were made to watch any of the resurgences. Perhaps these negative results were due to the fact that the streams were at a low level during our visit and an experiment with a larger quantity of dye might prove positive. The passage marked with an 'X' on the survey (at the top of the 117 ft. pitch) was followed and found to connect up again with the main cave near the big chamber.
Another approach to the problem would be to measure the heights more accurately. We believe that Gunnar Horn's surface survey is accurate and also the depth of the water at the bottom of the 117 ft. pitch was almost exactly 117 ft. below the lip during our visit. Consequently, it is only necessary to measure the depths of the caves with an accurate aneroid to obtain a more accurate correlation of the levels. (The expedition had been loaned a pair of very accurate altimeters, but to our regret we left them in Cambridge).
During our exploration of Lapphullet, various bones were found and taken back to Cambridge for identification at the Museum of Zoology. The genus only was given. "Rodent Passage" was so named because of a small skeleton (found under the 'D' of RODENT in the plan) and this was identified as Lepus (hare). Two other skeletons were found in the South entrance Passage, approximately fifty yards from the cave entrance and these were identified as Microtus (vole) and Lemmus (lemming). In his summary (page 77) Horn refers to the bones of Ursus arctus (brown bear), Lutra lutra (otter) and Lemmus lemmus (lemming), but it is not clear exactly where these bones were found. The bones found by us were all in the parts of Lapphullet not shown on Horn's survey.
Evidently Rodent Passage comes close to the surface (because of the bones) and another passage (Wilf's Passage) contains ice for the same reason. Gunnar Horn marks various cave entrances on the surface as being blocked by ice, but not all of these caves are above the ones we know. Another of the rising passages in Lapphullet is marked "dig" and at this point, we successfully removed a constriction only to find that the passage ended a few feet further on. We did not spend much time examining the surface as it was no encouragement to know that Gunnar Horn had spent several years in the area. The surface does contain small holes, however, and a further search might prove successful. (There is no resurgence beside the lake, for example).
Railton suggests (page 38) that the three caves might be part of the same system and our findings support this view.
Railton takes issue with Gunnar Horn concerning the manner in which water was supplied to the cave entrances during their formation. Horn suggested that they were covered by a glacier and that this would keep it more or less saturated with water, while Railton is in favour of the idea that the water level in Lake Reingardslivatnet was high enough to cover the cave entrances. In proposing his theory, Railton suggested that the bottom parts of the cave are constricted, and our observation about the absence of the sump is in agreement with this. However, we cannot agree with Railton when he quotes from Horn in his penultimate paragraph. Horn was, of course, well familiar with phreatic theories (see his bibliography) and Horn's wording would appear to be somewhat obscure in the sentence quoted by Railton. The word FAR below the water-table would appear to be the culprit and perhaps Horn expresses his meaning more clearly when he writes (page 75) "These passages were formed when they were completely water-filled". Acting on the assumption that formation was phreatic (or pseudo-phreatic) we can consider the manner in which mica-schist inclusions might have influenced the formation of the caves.
The phreatic formation of caves, as we have understood it, will take place in two stages. In the first stage, the fissures in the limestone are sufficiently small to prevent the free passage of water and an excess hydrostatic head is needed to produce any appreciable flow. Passage enlargement will be by solution and this state of affairs will continue until breakthrough occurs; and this is the beginning of the second stage. During the second stage, the passages are large enough to allow a considerable flow and passage enlargement can also occur because of the mechanical action of moving water (potholes, scalloping and suchlike), and during the second stage the flow will probably be sufficient to result in an adjustment to the level of the water-table. It would appear that the mica-schist is able to withstand attack by solution during the first stage, but it easily eroded mechanically during the second stage.
The passages were examined (particularly Lapphullet) to try to discover the manner in which the mica-schist flakes determined the formation of the passages. It was not possible to detect any of the original bedding in the limestone owing to metamorphism and it is necessary to examine the mica-schist inclusions in order to decide whether it is still meaningful to use the terms "dip" and "strike". Presumably, the mica-schist is formed from thin beds of shale in which case considerable folding has taken place about an axis running approximately East and West, and this is the direction of most of the cave passages. In some places, the mica-schist is not folded; and in such cases, the dip is towards the North, thus, insofar as the expression means anything, the caves would appear to lie very nearly along the strike. (A measurement on an exposed flat area of mica-schist, at the lower end of Rodent Passage indicated an apparent dip of thirty-three degrees, measured with the geological clinometer, along a direction approximately East of True North. This value agrees closely with Horn's published figure for the nearby cave, Olavsgrotten).
Railton noted that the roof is quite often an exposed mica-schist sheet, while the floor is hardly ever so. This is the observation that prompts one to suggest (above) that the mica-schist is able to resist attack by solution but it unable to withstand mechanical erosion. During phreatic conditions, moving water is more likely to drag debris along the floor than along the roof, and this would explain Railton's observation. In support of this, one would suppose that the mica-schist beds would stand proud from the walls in cavities more protected from the flow of the water; and this would appear to be the case. The best example of this, we found was in an aven about fifteen yards up the "Drainpipe" from the lower end of Rodent Passage, where a small cul-de-sac is almost completely filled with mica-schist flakes. The manner in which the mica-schist flakes project into the cave passages (and also some areas of mica-schist roof) can be seen from the photographs published by Horn, especially Plate 9, Figure 2 and Plate 15, Figure 1.
Gunnar Horn publishes a small-scale map on page 17, showing the positions of seventeen cave entrances, but this is not large enough to locate them on the ground. We used the topographical maps (1 : 1,000,000) for the areas Svartisen and Dunderlandsdalen. Gunnar Horn also includes a map showing the immediate vicinity of Lake Reingardslivatnet with the three cave entrances, to a scale of 1:40,000 and this would appear to be the previous map (1 : 100,000) drawn larger with further detail added. Holmsen published a geological map and also a map showing the distribution of caves in Rana. This latter map must be treated with some circumspection since, for example, Larshullet is marked incorrectly.
Further work had been suggested above regarding the more accurate measurements of altitudes, water-testing and passages requiring further attention. On a wider basis, Kirkland and Theakstone have been studying Gunnar Horn's work to find mention of several pitches awaiting attention; a cave awaiting entry, and sumps awaiting examination for diving prospects. They have also been reading the Norwegian caving literature (especially Holmsen) which they find to be more extensive than we had supposed. There are some caves awaiting entry and others the use of ladders, and it is unlikely that the forthcoming Cambridge University Caving Club's expedition will spend more than a few days at Lake Reingardslivatnet.
The expedition would like to express it thanks to the following firms for their generous assistance: Glaxo Laboratories Ltd., A. & R. Scott Ltd., Phillips Electrical Ltd., Cadbury-Fry Export Ltd., Batchelors Peas Ltd., Horlicks Ltd., George Romney Ltd., and British Ropes Ltd.. In addition, we would like to thank the Wessex Cave Club for the loan of some alloy tackle (to supplement the 100ft. owned by expedition members) and to various private individuals who also offered us equipment; to Mr. Lewis Railton for his helpful letters; to Mr. Maurice Black for discussions; to the local Geological Office in Mo-i-Rana for their interest and help (and for presenting a copy of Horn's work) and to the Geological Office in Oslo. In particular, we would like to express our thanks to Mr. & Mrs. Stormo, who on several occasions kindly offered coffee to members who found themselves stranded at the bottom of the hill.
Finally, I must add the disclaimer that this paper describes the work of seven men and that the words "we" and "our" includes them all. The preparation for this expedition was largely carried out by Dyson, Kirkland and Spowage and in Norway my own contribution was largely confined to exploring and surveying Lapphullet.
London, February, 1957.