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Popular Science Monthly/Volume 57/May 1900/Mount Tamalpais

MOUNT TAMALPAIS.
By MARSDEN MANSON, C. E., Ph. D.

MOUNT TAMALPAIS is the southern and terminating peak of the westerly ridge of the Coast Range, which confronts the Pacific Ocean from the Golden Gate to the Oregon line.

Its outliers form the bold headlands which skirt the Golden Gate and adjacent waters to the north, and which bound the peninsula constituting Marin County. The spurs extending to the east reach the shores of the Bay of San Francisco, and inclose small alluvial valleys of great fertility and beauty. In some instances these valley lands are fringed by tidal marshes, in part reclaimed and under cultivation.

The top of the mountain breaks into three distinct peaks, each reaching an altitude of nearly half a mile above sea level, although bounded on three sides by tidal waters.

No land points visible from the summit, except those bounding the apparent horizon, reach equal or greater altitude. The mountain is therefore a marked feature from all parts of the area visible from its summit, which area has an extent of about eight thousand square miles.

The adjoined photographic reproduction of a portion of a relief map of the State gives a general idea of the adjacent land, bay, and ocean areas.

The westerly group of islands, opposite the Golden Gate, are the Farallones. The bold headland northwest of the Gate is Point Reyes; it protects from the north and northwest winds the anchorage known as Drake's Bay. The strip of water between the adjoining peninsula and the mainland is Tomales Bay.

The most westerly headland south of the Golden Gate is San Pedro Point, and the prominent headland farther south is Pescadero Point. The whole of San Francisco Bay is visible from Mount Tamalpais, except a few sheltered nooks and portions behind islands.

The tidal area inside the Golden Gate is about seven hundred and forty square miles at high tide; this includes that portion which extends east of the Coast Range into the valley of California, and

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Vicinity of the Golden Gate.

known as Suisun Bay; this bay is connected with San Francisco Bay through the Straits of Carquinez and Sarn Pablo Bay. Emptying into Suisun Bay at its easterly end are the Sacramento and San Joaquin Rivers. Thus the tidal waters washing the base of Mount Tamalpais are connected with the interior valley of California, and tributary to them are about twelve hundred miles of navigable channels, tapping the central part of the State.

From the summit of this peak the eye sweeps the horizon of the Pacific Ocean for nearly one hundred and fifty degrees. To the northwest, north, and northeast lie Petaluma, Santa Rosa, Sonoma, and Napa Valleys, the view over these being bounded by the ridges inclosing them. To the east are the Straits of Carquinez, the outlet of the fifty-eight thousand square miles of drainage of the Sacramento and San Joaquin Rivers, and the only water gap in the entire perimeter.

From the east to the south lie the slopes of the Contra Costa Hills and the ranges bounding the drainage into the Bay of San Francisco, and including the Santa Clara Valley, thus embracing a magnificent view of the garden spots of California, and the cities and towns around the bay—the homes of about one third the population of the State. Three prominent peaks mark the limits of the land view: Mount Hamilton, the site of the Lick Observatory of the University of California; Mount Diablo, the base and meridian of the United States land surveys of central California; and Mount St. Helena, a volcanic peak the summit of which is common to Napa, Sonoma, and Lake Counties, and whose spurs are noted for their quicksilver mines, mineral and hot springs.

The plant life of the immediate Tamalpais region is abundant and interesting; the flowering plants are represented by about eighty orders, three hundred and fifty genera, and from seven to eight hundred species, of which about one hundred are trees and shrubs.[1] Some of the Sierra forms occur on Mount Tamalpais, and it is also the locus of the most southerly extension of certain boreal species. Owing to the wide range of temperature, moisture conditions, and exposures, many of these plants can be found in bloom during every week in the year. During the warm, moist

PSM V57 D081 Map showing railroad from mill valley to summit of mount tamalpais.png
Map showing Location of Railroad from Mill Valley to Summit of Mount Tamalpais.

autumn and winter the hardiest species bloom from October to April in protected areas, and in the cold, exposed areas these same species require the heat of the season from April to September to bring them into bloom. Thus, within a radius of four or five miles from the summit there is not a week in the year when the flowers of certain species can not be gathered—this in face of the fact that during the months of December, January, and February the summit may be covered with sleet or snow for a day or two at a time.

Mount Tamalpais is therefore a point of great interest to the sight-seer, the tourist, and the student of Nature.

Modes of reaching the Summit.—For many years a trail has existed from Mill Valley to the summit, and another from Ross

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View of Summit from a Point Sixteen Hundred Feet above Tide.

Valley, both practicable for pack mules. Later the Ross Valley trail was improved so as to be practicable for light vehicles, but these did not answer the needs of the increasing travel, and in 1895 the Mill Valley and Mount Tamalpais Scenic Railway Company was organized. The purpose of this company was bold—to construct a traction railroad from tide level to the summit of a peak not two miles off and nearly half a mile high appeared visionary, if not impossible, to many. But with persevering skill a road was located upon a line 8.19 miles long, having an average grade of five and a half per cent and maximum grades of seven per cent, and overcoming 2,353 feet elevation in this distance. Four and nine tenths miles are curved, the minimum radius being seventy feet. Owing to the rough and ravine-cut topography, twenty-five trestles were necessary, the curvature and grade being maintained over these.

In order to reduce the cost of grading and to develop sufficient length to overcome the elevation, the grade contour was followed as closely as possible. The very short radius employed permitted this to be done without tunnels and with but two through cuts.

The accompanying map, prepared from the United States Coast and Geodetic charts and the maps and profiles of the company, gives a general idea of the location and main features. To the student of railroad location it forms an interesting exhibit of the extreme flexibility of railway location.

The rails are steel, fifty-seven pounds to the yard, laid to standard gauge upon the ordinary redwood ties in use on the Pacific coast. Grading, trestle work, and laying cost about $55,000. The entire road cost $136,746.44, or practically $16,700 per mile.

The equipment consists of one thirty-ton geared locomotive (Heisler), one twenty-ton geared locomotive (Shay), six open canopy-top observation cars, one half-closed passenger car, and two flat cars. Cost of equipment, $22,450.[2]

The locomotives and cars are very thoroughly provided with brakes: first, the Westinghouse automatic air brake; second, a water brake; and, third, a powerful hand brake to each locomotive and car. The efficiency of this equipment is attested in the operation

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View from Summit of Mount Tamalpais Hotel at Terminus.

of the road without accident or injury of any kind. The locomotives are always operated on the lower end of trains, and the maximum speed allowed is eight miles per hour.

The ride up the winding canons and through the superb scenery traversed by this road is a treat of which one never tires. The point of view, the direction, and the character of the landscape are continually changing. With no deep cuts, no tunnels, facing first one and then the other and finally all the points of the compass, sweeping around spurs, with distant views of land and sea, and near views of great beauty; then facing the steep sides of the mountain, its geology and flora affording interesting pictures; then over trestles with the branches of the bay, redwood, madrono, oak, and manzanita just out of reach—all these form beauties and attractions possessed by no other road known to the writer. A faint idea of the appearance of the road and of the scenery may be had from the appended photographs.

The Meteorological Station.-—The advantages of Mount Tamalpais as a meteorological station have long been recognized, and

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The Double Bow.

many efforts have been made to utilize them. It frequently projects many hundreds of feet above fogs which cover the adjacent shores, and during these periods one can look out upon an ocean of rolling, fleecy clouds which break upon the mountains around its base and visible from its summit. This freedom from obscuring conditions gives an opportunity to more freely observe and study meteorological phenomena, and caused the Weather Bureau to make a series of preliminary observations in 1897, and, these resulting favorably, a fully equipped permanent station was subsequently built. The results have fully equaled expectations. The advantages of the location may be briefly summarized as follows:

1. It is close to the coast line, and is so elevated that it is not seriously affected by the local indraught of air through the Golden Gate and adjacent gaps in the Coast Range. This local indraught is a disturbing and often a misleading factor in all observations taken near and south of the Golden Gate for at least a score of miles. The elevated station on top of the peak eliminates the source of errors based upon observations at lower stations, and enables the forecast official to determine the effects of the local disturbances, and thus to give observations taken at or near sea level their true weight at the proper time.

2. 'No station in the United States has so full and free a projection into the lower third of the vapor-bearing stratum as has the station on this peak. No other station furnishes, as it does, an opportunity to study the distribution of vapor in the lower third of that stratum of the atmosphere, the physics of which is most important to human life and industries.

3. In studying the phenomena connected with the occurrence of fog, this station furnishes highly valuable data that could be obtained from no other; and, again, enables the student of weather lore to correct misleading impressions and deductions based upon observations taken below the one-thousand-foot contour above sea level.

On the 16th of June, 1899, the observations taken on Mount Tamalpais marked a difference of about thirty degrees in temperature over those around its base. In San Francisco, at Point Lobos and at Point Reyes, the temperature was down to 48°, while on Mount Tamalpais it was 79°, thus marking an approaching change in weather conditions, and giving the Weather Bureau the first opportunity of using the vertical temperature gradient in forecasting.

As a station for furnishing the data for a study of the problems of the physics of the atmosphere Mount Tamalpais is of further importance, as it stands near the easterly limits of the great area of high pressure which, during summer, lies over the North Pacific and which dominates the climatic phenomena of California for the greater portion of the year.

Stations on the Hawaiian Islands to the south and others on the Aleutian Islands to the north of this area of high pressure will still further aid in the solution of the great and vital problems now before meteorologists. These stations are the most reliable ones which can surround on three sides the two great "weather breeders"—the "summer high" and the "winter low" of the North Pacific.

  1. Estimated by Miss Eastwood, curator of the Department of Botany of the California Academy of Sciences.
  2. The writer is indebted to the officers of the Mill Valley and Mount Tamalpais Scenic Railway for the above accurate statistics.