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Modified from: D. Stanley Moulton, Leland Gilsen, Chris Laycock (1966). "Nutty PuttyCave: Utah County, Utah." Technical Note #63.  Salt LakeGrotto, National Speleological Society 

Nutty Putty Cave

Utah County, Utah

Rassle Knoll is one of several low desert hills east of Cedar Valley. Small weeds and sagebrush make up most of the sparse vegetation. Generally speaking the area is hot and dry, but is sometimes covered with snow during the winter. The fauna seems limited to rabbits, mice, snakes, lizards, and other small rodents and reptiles of the desert. The entrance of the cave often contains a few blowsnakes which can mimic rattlesnakes quite successfully. In ten trips to the cave, five snakes were encountered; one of which climbed onto Stan Moulton's back while he was entering a crawlway near the entrance. All the snakes found so far have been nonpoisonous, but care should be taken upon entering the cave.

The cave entrance is on nearly level ground in the saddle of a small spur of Rassle Knoll. MF-45 lists the formation as cherty limestone 120-140 ft thick. Very close to the west, is a bed of fossiliferous lime­stone and dolomite 380-400 feet thick; to the east is an extensive bed of Deseret formation. The cherty limestone near the entrance is probably what USGS Prof. Paper 107 (pp. 39-40) referred to as Gardner Dolomite.

The entire area is very fossiliferous; broken and badly weathered crinoid stems and horned coral are abundant. Prof. Paper 107 p.41 has a long list of identified varieties which indicate the limestone belongs to the upper Mississippian Era.

There is little doubt that the major speleogenesis of Nutty Putty Cave is phreatic, but there are some features that show minor vadose action. The development is primarily along the strike and down the dip, but is complicated by solution perpendicular to the dip which produced angular breakdown so characteristic of major sections of the cave.

Anciently the region has undergone an era of hydrothermal activity of five successive stages. First there was a hydrothermal dolomitization which also increased particle size and porosity, White to creamy vein­lets in the country rock were deposited at this time and consist of do­lomite and some calcite. The second stage was an argryllic alteration, which resulted in some "kaolinized" areas. Kaolinite is a clay-like Hydrous Aluminum Silicate (H4Al2 Si2O9). The third stage was a jasperoid alteration depositing some fine grained quartz. The fourth stage was a calcitic alteration. Zones of red hematite impregnated calcite occur throughout the area. This material, termed by Proctor "Ferruginous Calcite" may be the source of the red color in the "Navajo Blanket" formation in Blowhole Cave (TN 47, P.3). The calcitic alteration also caused some white to brown calcite and aragonite open space fillings on Wanlass Hill, one of them "large enough for a man to enter". This has not been checked, but no caves are known to the grotto on Wanlass Hill. There are also some calcite-quartz lenses bearing Hydrogen Sul­fide on Blowhole Hill. Occurring close to the calcitic stage in time was the last stage, when metallization occurred, and resulted later in the intensive mining activity of the area. (Proctor)

The altering fluids of this activity seem to have been hot dilute solutions of mixed chlorides, (MgC12, CaC12) and sulfides, H2S being the major compound. The country rock still bears some Hydrogen Sulfide. These may have been the primary dissolving agents in the caves phreatic history, or perhaps played a significant part in the chemistry of the dissolving process.

Nodules of chert are exposed throughout the cave and are apparently the source of much of the mud and silt found inside. In the damper por­tions of the cave it is soft, while in other areas it is very hard. When it is damp and crumbly, light and rapid squeezing will cause it to change to a viscous fluid about the consistency of warm honey. If it is allowed to dry and then is worked again, it takes on the feel and characteristics of the synthetic compound sold in toy stores under the name of Nutty Putty. The cave gets its name from the abundance of this material which looks like it is slowly oozing from the walls because of the way the limestone has dissolved around it leaving it protruding out at odd angles. Though not so aesthetically pleasing as calcite formations, it is nevertheless very interesting and irreplaceable. Visitors to the cave should be very careful to preserve them in their original form. Several samples of the "nutty putty" have been analyzed, and it appears to be composed of minute rounded particles of Silicon Dioxide, roughly three microns in diameter, and some minor impurities.

The "nutty putty" immediately presents two problems; what its physical properties are that cause it to have its peculiar characteristics, and where it came from and how it got there. As the origin of chert in general is not thoroughly understood, the solutions of these problems may well have to await some very extensive research. But it is interesting to note some at least superficial resemblances of the "nutty putty" to the "quick clay" which causes so much damage in Norway, Sweden, and parts of Eastern Canada. A slight shock will turn this clay to a liquid, and large sections of the earth will go cascading down very gentle slopes. The breaking of the transatlantic cables on Nov, 18, 1929 has been attributed to such a slide traveling underwater at about 14 miles per hour down a slope of only 1 degrees , after having been started by a minor earthquake off the Newfoundland coast. Kerr (p 134) lists the following physical properties for quick clay to be unstable: (1) a layered fine structure of flakes made up of various silicate clay minerals such as illite, monmorillonite, chlorite, and kaolinite, (2) particles less than 2 microns in diameter, (3) a high water content, usually greater than 50% by weight, (4) the water is low in electrolytic salts which bind the particles together, usually less than 5 gm, per liter (sea water has 35 gm. per liter of salts). These clays were formed by a glacial pulverizing of the various silicate minerals and their subsequent deposition on the sea floor during the Pleistocene Epoch. The sea floor was later lifted and the salts washed out by fresh water. The particles tend to be dispersed by organic and some alkaline earth acids. (Kerr)

Some of the chief differences between the "nutty putty" and the "quick clay" are in the slightly greater particle size of the "nutty putty" and the more spherical shape. The nutty putty originally breaks in preferred directions, indicating an ordered arrangement of particles, while "quick clay" has flat particles randomly arranged like an unstable card stack. And of course the "nutty putty" is much older and has a far greater history including, no doubt alteration by the hydrothermal activity mentioned earlier.

The presence of fossil negatives and lack of positives indicates very little or no replacement by calcium from ground water. It would be of interest to see if dried "nutty putty" redissolved in water containing a high proportion of some electrolytic salt would be as "nutty". There is some slowly dripping water in a few places in the cave, and the walls are usually damp throughout. Another interesting property of the cave is that it is a very strong blowing cave like others in the vicinity, but it does not appear to have a lower entrance. A connection with a nearby mine seems remote,

Biologically speaking, Nutty Putty contains the usual fungi growing in rat droppings, but no other plant life was observed. There is a family of mice in a small nest near the entrance which are usually unafraid of people. Cave crickets are often observed near the entrance, and on one occasion a number of very small ones were seen about 20 ft from the entrance. On another occasion a large number of crickets were found grouped together just inside the entrance, upon emerging from the cave we found that it had been raining outside. According to Moore and Nicholas (p. 75) they leave the cave to feed only when the humidity outside is exceptionally high, and it seems likely that the crickets we saw were just returning. We have no idea how the crickets knew what the humidity was outside; nothing gave us any clues. Each trip usually means crawling over some "stinkbugs" in the entrance, they seem to prefer the warm humid air that blows from the cave. No biological identifications have been made; the crickets seem to be somewhat smaller than those described by Moore and Nicholas, and could prove to be very interesting.

Also as of yet unidentified are the bones of a large mammal found at the bottom of the entrance sink. Unless they are to be identified, they should not be disturbed. There is also the articulated skeleton of a rabbit in a small crawl southeast of the entrance, and some more small mammal bones in the northern section of the cave.

No section of the cave gave any evidence of occupation by primitive peoples, in fact the cave shows remarkably little evidence for use by modern man. Very little vandalism is in evidence, but the general structure of the cave does not lend itself to show disturbance because of its broken nature, and there are no extensive limestone formations that might encourage it.

The entrance of the cave is a small sink which leads to a short muddy crawl. After this the going is easier, the numerous drops indicated near the entrance are small and easily climbed, the biggest being at the bottom of the "Big Slide". Its 15 ft can be chimneyed without undue difficulty, but a short handline is a great advantage when coming back up over the edge. The wall holds a piton fairly well in this area.

The southern part of the cave ends in a solution complex of tight squeezeways which eventually pinch off. Some of these are real challenges, but the small formations and the red clay fins inside "Bob's rush" are of interest to the very skinny. Also on the ceiling of the crawl are three or four very tiny gypsum flowers.

North from the entrance, Karl's crawl and some other very small connections are recommended only for masochists. They are only of interest to show spatial and hydrological relationships, and to show what has been pushed and where it went. One of the fossils here forms an extensive lacy pattern and is very unusual. The "Greated Slanted Slot" is not the big room it appears to be on the map; it is actually a very narrow slot set at about a 1.50 angle. Farther along are some "blisters" formed by the limestone dissolving away in back of a filled joint, and some chert nodules covered with some buff colored material. Just inside the last room are three slabs of limestone with dabs of calcite randomly arranged like paint on an artist's palette. When first seen aye was precariously balanced on another rock, but it was inadvertently disturbed and fell. Coral is present in a few pits along the way, and in a few places it overlies some tiny greenish blue crystals.

The general possibilities for rushing this cave seem almost unlimited, but it will take time and energy. Some of the best possibilities lie around the "Big Room" where several cracks appear to open up onto unexplored areas, but this kind of caving will be mostly excavation.

The surface topography suggests drainage to the southeast in the southern end of the cave, and to the northeast in the northern end, as the entrance sits just to the west of a saddle that runs east and west. The strata in the cave and on the surface strikes about N14 degrees W, the same direction as the cross hatching on the map, and dips about 57 degrees East. Another new possibility is a new sink forming approximately 700 ft S15 degrees E of the entrance of nutty putty with a small amount of air blowing from it. Almost in line with it is another smaller sink approximately 500 ft from the Nutty Putty entrance. This may mean more cave paralleling the northern section, but with no known entrance in Nutty Putty itself. It would have the same sort of drainage as the southern part of Nutty Putty. There remains also the very remote possibility that there is a relationship between Nutty Putty and Rassle Knoll Pit.

A little back breaking excavation may very possibly open up significant additions to the known cave in this area.


Green, Dale J. "Basic Speleology of the Aliens Ranch and Boulter Mountains Quadrangles, Utah and Tooele Counties, Utah" Technical Note #47, Salt Lake Grotto National Speleological Society, October 1958.

Kerr, Paul F. "Quick Clay", Scientific American, Vol. 209, #5, November 1963, p. 132-14O.

MF 45 "Preliminary Geologic Map of the Aliens Ranch quadrangle, Utah." Mineral Investigations Field Studies Map MF 15. By Proctor, Paul D. and others. U.S.G.S., 1956.

Moore and Nicholas Speleology, The Study of Caves. D. C. Heath and Company 1961.

Proctor, Paul D. "Fringe Zone Alteration in Carbonate Rocks, North Tintic District Utah" Economic Geology, Vol. 59, Dec. 1961. p. 1561-1587.


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