Dunderberg Mountain

Route 9W/202, Jones Point, Bear Mountain State Park, Rockland County, New York


parking pull-off is a short distance south of Iona Island.


There are four parking areas along Route 9W/202 for four different trails:

1) just north of the road to Iona Island parking for the blue-blazed Cornell Mine Trail;

2) just south of Jones Point for the red dot-blazed Ramapo-Dunderberg Trail;

3) a little ways south of the #2 parking area for the blue-blazed Timp-Torne Trail;

4) south of the Anchor Monument (across the railroad tracks on the river bank) for the red-blazed 1777 Trail.


Dunderberg Mountain, the backbone of Jones Point, is on the upthrown, or Hudson Highlands side of the Thiells fault and is held up by granitic gneiss similar to that of Bear Mountain and Storm King Mountain.  (Van Diver 1985: 65)


Colonial Period  --  some iron mines up in the hills back of Dunderberg.

1777 (October 6) -- the 1777 Trail marks the route taken by the British under Sir Henry Clinton to attack forts Montgomery and Clinton).

1889  --  Henry J Mumford comes to the area looking for a place to place a "Switch Back" railroad. Mumford and his brother operated a scenic "Switch Back" railroad in Mauch Chunk (now Jim Thorpe), Pennsylvania,. This type of railroad was a popular tourist attraction in the second half of the 19th century.  Mumford thought he could attract many visitors with a spiral railway in the greater New York City Metropolitan Area.  Visitors could come to Dunderberg via excursion rides on the Hudson River steamboats.

1890  --  a million dollars was invested in the construction of the Dunderberg Spiral Railway that began this year.  The money ran out and the work was closed.  

1906-1908  --  William Thompson Howell, hiker and photographer, re-discovered the Spiral Railway.  He went up today's Bockberg Trail and down the Jones Trail to find the abandoned railway works.

1910 (May 14-15)  -- As William T. Howell (1982:158) and patent attorney Clair Fairbank crossed the high shoulder of the Dunderberg formation west of the big hollow they faced "an unusual and amusing incident" that Howell summed up in the one word --  Cows!  They had come upon some mountain cows that had come all the way up the mountain from the Doodletown clove along the route of a wood road. 

1910  --  the clearing around the inclined planes was still visible.

1933 and 1934  --  extracts of Howell's diaries  published as two volumes called The Hudson Highlands.

1978  --  park official Gordon J Thompson reported "with noted exceptions, the grade is in excellent condition and could be envied by the county's operating railroads".

1982  --  Howell's diary extracts reprinted by the Walking News.

(Source: for a fuller account see Dunderberg Spiral Railway -- http://www.columbia.edu/~brennan/dunderberg/begin.html)

The Timp-Torne Trail follows one of the graded sections of the spiral railway.


7/10/04.  Went with my friend Philip Duckett to take the Timp-Torne Trail (TT Trail).  We parked and then walked south a little ways along Route 9W to pick up the TT Trail.  The base of the mountain is simply and absolutely covered with invasive plants.  Black swallowwort covers a great many areas and also covers larges patches up along the mountain trail. Porcelain berry climbs up and over trees. Asiatic bittersweet is as pesky as ever, along with multiflora rose.  The trail maintainers must have to come out here quite frequently to stop the invasive plants from completely covering the path.  As it was, we had to dodge branches of multiflora rose and other species as we walked along the base of the mountain.

After a very short climb, the hiker comes to the lower tunnel.  The far end of the tunnel was left unfinished with the ends of some of the large blocks of rock sticking out of the tunnel arch.    Climbing it is interesting to watch for the paths that look like they were graded for the spiral railway.

Most of the trail up the mountain is gradual which makes for an easier walk.  A short walk brings the hiker to a lookout point where the nuclear plant at Indian Point looks like it is just across the street.  Since the trail is a switch-back, the view of Indian Point remains as one climbs.  But higher up one gets a good look at the Hudson River south of Indian Point. 

Along the way we were excited to see a five-lined skink. 

Came to the upper tunnel.  This time there was no water in the tunnel, so we walked into the dark space.  It is a short walk because the tunnel was never finished.  Given how dark the tunnel entrance appeared, it was surprisingly light in the tunnel after our eyes adjusted to the dark.  We could see how the tunnel workers worked on top of a ledge to cut deeper into the mountain.  

The path continues around to the back of the tunnel area where one can see a canyon looking area.  This was the point to where the tunnel was supposed to connect if it had been finished.

Nearer the top of the mountain it was a treat to see one of my favorite plants, goat's rue.  It was not in bloom, unfortunately.  The flowers are yellow and pink with purple markings.

Dr. Patrick L. Cooney
* = plant blooming on date of the field trip, 7/10/04

Acer negundo (ash-leaf maple)
Acer pensylvanica (striped maple)
Acer rubrum (red maple)
Acer saccharum (sugar maple)
Ailanthus altissima (tree-of-heaven)
Aralia spinosa (Hercules club)
Betula alleghaniensis (yellow birch)
Betula lenta (black birch)
Carya glabra (pignut hickory)
Carya tomentosa (mockernut hickory)
Fagus grandifolia (American beech)
Fraxinus americana (white ash)
Juniperus virginiana (red cedar)
Liriodendron tulipifera (tulip tree)
Morus alba (white mulberry)
Ostrya virginiana (American hop hornbeam)
Paulownia tomentosa (princess tree)
Pinus rigida (pitch pine)
Populus deltoides (cottonwood)
Prunus serotina (black cherry)
Quercus alba (white oak)
Quercus prinus (chestnut oak)
Quercus rubra (red oak)
Quercus velutina (black oak)
Robinia pseudoacacia (black locust)
Salix sp. (willow)
Tilia americana (American basswood)

Berberis thunbergii (Japanese barberry)
Cornus florida (flowering dogwood)
Elaeagnus umbellata (autumn olive)
Gaylussacia baccata (black huckleberry)
Kalmia latifolia (mountain laurel)
Lindera benzoin (spicebush)
Lonicera morrowii (Morrow's honeysuckle)
Rhus typhina (staghorn sumac)
Rosa multiflora (multiflora rose)
Rubus occidentalis (black raspberry)
Rubus phoenicolasius (wineberry)
Salix discolor (pussy willow)
Vaccinium pallidum (hillside blueberry)
Vaccinium stamineum (deerberry)
Viburnum prunifolium (blackhaw viburnum)

Ampelopsis brevipedunculata (porcelainberry)
Celastrus orbiculatus (Asiatic bittersweet)
Lonicera japonica (Japanese honeysuckle) 
Parthenocissus quinquefolia (Virginia creeper)
Polygonum perfoliatum (mile-a-minute vine)
Toxicodendron radicans (poison ivy)
Vincetoxicum nigrum (black swallowwort) * lots of it

Achillea millefolium (yarrow)
Alliaria petiolata (garlic mustard)
Allium vineale (field garlic) *
Antennaria sp. (pussytoes)
Apocynum cannabinum (Indian hemp)
Arctium sp. (burdock)
Artemisia vulgaris (common mugwort)
Asclepias syriaca (common milkweed)
Asparagus officinalis (asparagus)
Aster linariifolius (stiff aster)
Chrysanthemum leucanthemum (ox-eye daisy) *
Cichorium intybus (chicory)
Circaea lutetiana (enchanter's nightshade) *
Cirsium arvense (Canada thistle) *
Cirsium vulgare (bull thistle)
Cunila origanoides (dittany)
Daucus carota (Queen Anne's lace) *
Dianthus armeria (Deptford pink) *
Echium vulgare (viper's bugloss) *
Galium circaezens (wild licorice)
Geum canadense (white avens) *
Hieracium sp. (hawkweed) *
Hieracium venosum (rattlesnake hawkweed)
Hypericum perforatum (common St. Johnswort) *
Impatiens sp. (jewelweed)
Lactuca canadensis (wild lettuce)
Lechea sp. (pinweed)
Lespedeza hirta (hairy bushclover)
Linaria vulgaris (butter and eggs) *
Linum virginianum (wild yellow flax) *
Melilotus alba (white sweet clover) *
Melilotus officinalis (yellow sweet clover) *
Monarda punctata (horsemint) *
Oxalis sp. (yellow wood sorrel) *
Paronychia canadensis (forked chickweed)
Pilea pumila (clearweed)
Plantago lanceolata (English plantain) *
Polygonatum pubescens (hairy true Solomon's seal)
Polygonum cespitosum (cespitose smartweed) *
Polygonum virginianum (jumpseed)
Potentilla simplex (common cinquefoil)
Prunella vulgaris (self-heal) *
Pycnanthemum virginianum (Virginia mountain mint) *
Saponaria officinalis (bouncing bet) *
Satureja vulgaris (wild basil) *
Silene vulgaris (bladder campion) *
Solidago juncea (early goldenrod)
Tephrosia virginiana (goat's rue)
Trifolium pratense (red clover) *
Triodanis perfoliata (Venus looking glass)
Verbascum thapsus (common mullein)
Verbena urticifolia (white vervain) *
Veronica officinalis (common speedwell)

Juncus effusus (soft rush)
Juncus tenuis (path rush)

Carex laxiflora type (loose-flowered sedge type)
Carex pensylvanica (Pennsylvania sedge)
Scirpus cyperinus (woolly grass bulrush)

Bromus inermis (smooth broom grass)
Dactylis glomerata (orchard grass)
Danthonia spicata (poverty grass)
Deschampsia flexuosa (hair grass)
Elymus hystrix (bottlebrush grass)
Microstegium vimineum (Japanese stilt grass)  -- lots of it (carpets of it)
Panicum clandestinum (deer-tongue grass)
Phragmites australis (giant reed grass)

Ferns and Fern Allies:
Asplenium platyneuron (ebony spleenwort)
Athyrium filix-femina (northern lady fern)
Dennstaedtia punctilobula (hay-scented fern)
Dryopteris marginalis (marginal woodfern)
Onoclea sensibilis (sensitive fern)
Polypodium sp. (rock cap fern)
Polystichum acrostichoides (Christmas fern)
Thelypteris noveboracensis (New York fern)