Santa Cruz County History - Making a Living

The Laguna Limekilns: Bonny Doon
by Robert W. Piwarzyk

[This article is excerpted from a manuscript titled, "The Laguna Limekilns: Bonny Doon," pp. 44-45. The maps, drawings, and photos of the manuscript are not included on this site. The manuscript is copyrighted 1996 by the author. It is used here with permission.]

Site Location

The Laguna limekilns and quarries are located in Santa Cruz County, in the Santa Cruz mountains, in Bonny Doon, California, approximately 5 road miles west of Felton. The site is within the southeast quarter of section 13 of township 10 S, range 3 W; and the western half of section 18 of township 10 S, range 2W. The site is from 1450' to 1600' elevation on the southwestern slope of Ben Lomond Mountain, where Ice Cream Grade crosses Laguna Creek. Santa Cruz County Surveyor bench mark 361 indicates an elevation of 1658.13 feet on Ice Cream Grade above the kilns. There is excellent agreement with this bench mark, the topographic lines on the USGS Davenport quadrangle map, and the site survey.

Unrecorded map A56-13 of Arnold Baldwin (undated, but known to be before 1938) for the lands of McLaughlin & Holmes Lime Company notes the quarter section corner on the eastern boundary of section 13, township T.10.S.R.3.W. as follows:

1" iron pipe for 1/4 sec. cor. (as per U.S. Deputy Freeman's returns) 8" T.O. N 360 W 10. 36" yellow fir (U.S. Deputy Craven's survey) S 220 W 36.73. 24" R.W. stump 1/4 s. cor by U.S. Deputy Foreman south 378.34 and east 48.36 (see Freeman's returns)

T.O. and R.W. indicate tan oak and redwood. Distances are in feet. This iron pipe and the witness trees were also surveyed by Tom Williams of Bowman & Williams of Santa Cruz in the 1940s, and was observed by the author in 1982 after flood waters washed away a log jam. The pipe is in the creekbed, downstream of the culvert under Ice Cream Grade, in the western channel of Laguna Creek (just downstream of the fork in the creek) and is currently buried again under debris.

This industrial site has never been designated with a California Archeological Inventory Number (CA-SCr-XXX) according to Cabrillo College records.

Site, sections, townships, bench mark, and ¼ section corner locations are shown on the maps and site plan in the appendix. [Not included here.]

Site Description

Uplifting and canyon erosion of the coastal range has exposed outcroppings of limestone, metamorphosed sandstone, and quartzite in the Laguna Creek watershed. Rainfall is adequate to support a mixed evergreen forest of redwood, fir, madrone, and tan oak, thus providing a source of fuel for burning the limestone. The site is divided north to south by Laguna Creek, and east to west by an unnamed intermittent creek. Downstream, Mahan Gulch follows Ice Cream Grade out of the canyon to the west. Limestone occurs on both sides of these ravines, from the creek beds to the ridgelines above. Ice Cream Grade, which served the kilns, hairpins through the narrow area upstream of the site to cross Laguna Creek. Within the hairpin lies one of the few small, wide alluvial flats to be found on Laguna Creek which generally flows through a narrow, steep-sloped canyon. It will be helpful to refer to the maps, site plan, drawings, and photographs in the appendix. [Not included on this site.]

On the east side of Laguna Creek, downstream of Ice Cream Grade, are two hillside limekilns. These side-by-side, pot kilns ("left kiln" and "right kiln") are constructed of large blocks of limestone from the adjacent quarry. They are graced with a carpet of algae, lichens, mosses, ferns, and occasional mushroom. A second growth stand of redwoods are growing in front of the kilns but do not seem to have any adverse effect. These trees block out the sunlight and maintain dampness in the area.

The floors of the large quarries to the south (downstream) are approximately 30' and 80' above the kiln floors. Quarry tailings were dumped on the west-facing slope on Laguna Creek below these two large pits. Other smaller quarry pits are located on the ridgeline above these large quarries. There are also pits upstream of the site on the unnamed creek to the east. The upper quarry has a section of two-foot gauge rails protruding from the limestone rubble. The lower quarry has a grade cut for a tramway and a bridge crossing to the kilns.

A large cast iron 6 ½' diameter pulley is located approximately 85' above the top of the kilns. This sits on an earthen platform retained with a 6' stone wall. Anchor cables and a small quarry pit are uphill of the pulley. A bearing 90 degrees to the center of the wall sights down to the two A-frame structures found at the top of the left kiln. Although no cable or ore cars were found, it seems reasonable that an aerial tramway was used at some point of the operation.

Rails, ties, and spikes for a three-foot gauge tramway were found buried beneath the loop road along the top of the kilns. It is possible that the larger gauge tramway was used only during construction of the kilns to bring larger, heavier rock for the kiln walls to the site. The rails extend south beyond the right kiln and curve to the east up the side ravine.

The area has several logging and skid roads radiating out from the kiln site. One skid road is still in place upstream of the waterfall on the east fork of the creek. One road extended through the upper canyon all the way to Atherly Way. Part of this is now the lower part of the driveway at 1373 Ice Cream Grade. Notches for spring boards are seen in most of the remaining virgin redwood stumps. The canyon is entirely second growth. Part of the canyon may have been logged for lumber prior to the Holmes Lime Company logging for fuel for the kilns.

Judging from the sizes of the kilns and the quarries, not too many loads were fired. Kiln waste was dumped on both sides of Laguna Creek from the bridge to the confluence of the creeks and was used as fill to build up the work areas. Greater use of this site would have produced more waste. There is no kiln waste to be seen downstream of the site. Action of streamflow great enough to carry such waste would most likely cause it to crumble.

An access ramp from the entry road from the north to the top of the kilns circles around to the south and back down to kiln floor level. This was a turn-a-round loop for the dead-end road that served the site. It would seem that wagons would have adequate room to turn around in front of the kilns, but this area would normally have had cords of wood stacked up for fuel, and empty or loaded barrels. A loop was certainly easier than backing up a horse-drawn wagon. Also ore brought to the site by wagon could be unloaded into the top of the kiln.

The Bonny Doon planning area map, dated 24 May 94, indicates that the current land use is "public facility," as it is Santa Cruz City Water Department watershed property. It is also shown within the coastal zone. The natural & cultural resources protection, production and extraction maps indicate that it is scenic, riparian corridor, timber, ground water recharge, and water supply watershed land.

The kilns, quarries, tramways, pulley and A-frame are discussed in more detail in separate sections of the report. The site plans, plan view and section, are presented in appendix B. [Not included on this site.]


The best general description of the geology of the Santa Cruz mountains can be found in the introduction to John Hunter Thomas' "Flora Of The Santa Cruz Mountains." It was written by Earl E. Brabb, School of Mineral Sciences, Stanford University. Thomas included this on the premise that the diverse plant communities found in these mountains could be described by their habitat --- climate and soil --and that geology was a useful tool for understanding this. It is written for the novice, and well worth reading. More technical information is available, but only a limited amount is presented here to provide some background.

The geology of Ben Lomond Mountain is very complex and Laguna Canyon seems to have all the components concentrated into a small area. There are several kinds of limestone to be found here, all of which are metamorphic. The fractured outcrop on Laguna Creek upstream of Ice Cream Grade is pure marble with large white crystals. This is low grade marble, but limestone in the Santa Cruz mountains is often classified as marble as it just passes the hardness test. Ore of this quality does not appear to be abundant in the nearby quarries. There is a waterfall upstream that is caused by the slow erosive rate as the creek crosses a vein of this type of limestone. On the west side of the creek, uphill of Ice Cream Grade, the limestone is grey and more granular. When broken open, it smells heavily of sulphur and has dark, parallel ribbons running through it. This type of fetid limestone is called "stinkstein." The quarries have a solid grey, granular ore which is occasionally coated with flowstone which forms in the manner of stalagtites in caves. This is most likely due to ground water flowing through the many fractures found in these deposits.

Gold was reported as having been found in Laguna Creek in the late 1800s. As recently as 1952, small quantities of very fine flakes were found using electronic metal detectors. Iron pyrite --- "fool's gold" --- found in abundance in the creek is easily confused with this "color."

On the following pages a detailed map of the limestone quarries, pits, and outcroppings located in the vicinity of the Laguna limekilns [not included on this site], and a description of the deposits is presented. This description states that no quarry was identified, which may not be unreasonable as this author only located the quarries five years after first visiting the kilns!

Appendix B has further information on the geology of the upper canyon. The composite map entitled "The Limekilns and Roads of Bonny Doon" shows the locations of limestone deposits in the lower canyon, upstream of Smith Grade, as surveyed by the Santa Cruz Portland Cement Company in 1911. [Not included here.]

"Ice Cream Grade deposits. Location: SE ¼ sec. 13, T. 10 S., R 3 W. and W ¼ sec. 18, T. 10 S., R. 2 W., M.D., 3 ½ miles west of Felton; Ben Lomond 15 minute quadrangle. Ownership: not determined (1963).

Several small limestone deposits are exposed along Ice Cream Grade road in the vicinity of Laguna Creek. The limestone is crystalline and forms well-defined massive beds interlayered with schist and quartzite. These small deposits are somewhat impure and appear to be of little or no economic interest.

Two old stone limekilns, situated on the east bank of Laguna Creek just south of the Ice Cream Grade road, testify to early efforts to develop limestone in the vicinity. The kilns are identical; each measures 15 feet by 21 feet on the inside, and both are completely open at the top (no stack). No limestone quarry was identified in the area, and there is evidence that only a little lime was burned. A quarry location and the general distribution of limestone outcrops is indicated by Branner 1 et al. (1909 map) and Leo 2 (1967, p. 30)." 3

1 Branner, J. C., Newsome, J. F., and Arnold, R. 1909. Description of Santa Cruz quadrangle, California: U. S. Geological Survey Geologic Atlas, Santa Cruz Folio, no. 163, 11 p.
2 Leo, G. W. 1967. The plutonic and metamorphic rocks of the Ben Lomond Mountain area, Santa Cruz County, California, in Short contributions to California geology: California Division of Mines and Geology Special Report 91, pp. 27-42.
3 Hart, Earl W., Limestone, Dolomite, and Shell Resources of the Coast Range Province, California; Bulletin 197; California Division of Mines and Geology, 1978, p. 48.

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