Ludlowville Falls, NY

From the park overlook, you get a wide view of Ludlowville Falls. In the shade to the left (out of the picture) there is a "cave" eroded into the shale and roofed by the Tully formation. (ref. # D060797) © Dave Spier

From the park overlook, you get a wide view of Ludlowville Falls. In the shade to the left (out of the picture) there is a “cave” eroded into the shale and roofed by the Tully formation caprock. (ref. # D060797) © Dave Spier

Ludlowville Falls is on Salmon Creek in the Town of Lansing on the east side of Cayuga Lake in New York’s Finger Lakes region. The height of the falls is listed variously as 35′ to 45′ so we’ll just round it to 40 feet and be done with it. A public park provides easy access to an overlook. For the more adventurous, including fossil hunters, a trail descends to the lower creek bed, or you can park downstream at a fishermen’s access and walk up the creek. (Note: We haven’t taken the time to explore either of these options yet.)

Falling water reflects sunlight to create a rainbow. The rock behind the rainbow is Hamilton-group shale deposited in a shallow inland sea during the middle Devonian period. (ref. # D060922) © Dave Spier

Falling water reflects sunlight to create a rainbow. The rock behind the rainbow is Hamilton-group shale deposited in a shallow inland sea during the middle Devonian period. (ref. # D060922) © Dave Spier

The falls is capped by massive layers of Tully limestone deposited in a shallow inland sea during the Devonian period. The soft, underlying Hamilton-group shale is easily eroded and allows blocks of the limestone to break along joint planes and fall into Salmon Creek. Under the south edge of the falls, shale erosion continues to create a large “cave” roofed by the Tully. A very slight strata dip to the northeast results in water flowing over the straight edge of the falls only during spring runoff or following heavy rain storms.

A small, hidden flume creates this "rooster tail" plume. Can you find it in the opening photo? (ref. # D060919) © Dave Spier

A small, hidden flume creates this “rooster tail” plume. Can you find it in the opening photo? (ref. # D060919) © Dave Spier

The nearly-flat sedimentary strata across the Finger Lakes region has mainly a slight southerly dip. Combine this with the gradual, northward descent of the land to the Lake Ontario plain and you get a low escarpment where the Tully limestone outcrops on the surface. Unfortunately, Ice Age glaciers essentially obliterated much the Tully escarpment, so it doesn’t have the prominence of the Lockport dolostone to the west (in the Niagara region) or the Onondaga escarpment to the east (around Syracuse and beyond).


This view locates the “rooster tail” below the massive Tully limestone caprock. (ref. # D060795) © Dave Spier

Tully limestone also creates the lower falls at the mouth of the Taughannock gorge just upstream from the delta. West of Seneca Lake, the Tully is exposed at a falls on Kashong Creek in the hamlet of Bellona midway between Penn Yan and Geneva. South of that falls is another one exposed at Cascade Mills on the Keuka Outlet between Penn Yan and Dresden. That and the Seneca Mill falls are easily accessible from the Keuka Outlet Trail, but we’ll save them for another blog post.

Pothole in a block of Tully limestone down on the lower streambed... (ref. # D060920) © Dave Spier

Pothole in a block of Tully limestone that dropped down to the lower streambed… The flat sides follow joint planes. (ref. # D060920) © Dave Spier

Directions to Ludlowville: From the south take Route 34 north from Ithaca, turn left (west) on Route 34B in South Lansing, continue to Ludlowville Road, and turn right for a short distance. The park will be straight ahead, just across Salmon Creek Road / Mill Street. It’s then a short walk across the grass to the fence overlooking the falls. From the north, Routes 34/34B connect Auburn to Ithaca.

For more information, there is a facebook page devoted to the falls. It’s emphasis is fossil hunting.

For a regional waterfall guidebook or a downloadable e-book version, buy 200 Waterfalls in Central & Western New York – A Finder’s Guide by Rich & Sue Freeman. It covers the area from Niagara to Utica and Jamestown to Binghamton. Ludlowville is on pages 236-237 of the 2002 edition. Also check their website for updates to the book.

Corrections, comments, and questions are always welcome at or connect through my Facebook page and photo page. For topics in the northeast, there is a separate community-type page at The Northeast Naturalist. Other northeast nature topics can be found on the parallel blog Northeast Naturalist.

Taughannock Falls


winter view of Taughannock Falls from the overlook on Park Road
© Dave Spier (ref. # 0016EX-24)

Taughannock Falls, NY (USA) — © Dave Spier

photos © Donna Mason-Spier, unless otherwise noted

The highest single-drop waterfalls in New York State is accessible from Rt. 89 northwest of Ithaca in New York’s Finger Lakes region. Taughannock Creek flows east as it descends the west slope of the Cayuga Trough to end in Cayuga Lake where it has created a flat delta. Since the end of the last Ice Age, two significant waterfalls have cut an impressive gorge into the Allegheny Plateau. To get a better overview of the park, I suggest first starting at the falls overlook on the north rim about a half mile uphill from Rt. 89. You’ll see part of the lower gorge below the main falls, the 400′ high amphitheater surrounding the falls, and you can glimpse the upper gorge above this falls. Further uphill (either by driving or by waking the rim trail) you can reach the old railroad bridge over the upper gorge and view the upper falls just below Falls Road.

Drive downhill on Taughannock Park Road and turn right (south) on Rt. 89, cross the creek and pull into the lower parking lot on your right. (In warm weather, if this lot is full, there are larger lots on the east side of Rt. 89, toward Taughannock Point, the delta created from sediments washed out of the hillside.) If you happen to return via Gorge Road on the south side, it would be a left turn at Rt. 89.


The lower falls capped by Tully limestone – © Donna Mason-Spier (ref. # D075270)

After a short walk from the lower parking area, you can see the first, fairly-low falls created by the resistant Tully limestone caprock.  Weak Hamilton shales at the base of this falls easily erode and allow blocks of the Devonian-age limestone to break off.


Joints (long cracks) cross the Tully limestone above the lower falls and result in step falls.- © Dave Spier (ref. # D062962)


Solution pits pock-mark the surface of the Tully limestone. – © Donna Mason-Spier (ref. # D075188)

As you can see in the photos, it’s possible to walk down to the creek bed and examine the solution pits on the limestone surface.


A “step” falls formed by an upper stratum of Tully limestone – © Donna Mason-Spier (ref. # D075191)

Above the lower falls, the creek has washed off the relatively flat surface of the Tully up to a wide “step” falls created by another layer of the limestone.  Above that, flat surfaces with minor steps continue upstream until they disappear under the dark, almost-black Geneseo shale. Along much of the three-quarter mile walking trail up the lower gorge, you’ll have first-hand access to this weak shale that crumbles and piles into talus slopes at the base of the cliff walls.


Black Geneseo shale forms talus slopes beside the lower gorge trail.
© Donna Mason-Spier (ref. # D075193)

If you look above the dark shale, you’ll see the beige cliffs formed by more resistant Sherburne siltstone, slightly younger rock overlying the Geneseo formation. Both are members of the upper Devonian Genesee group.


Beige cliffs of Sherburne siltstone overlie the dark Geneseo shale on the gorge walls. – © Donna Mason-Spier (ref. # D075246)

As you continue upstream to the base of 215′ high Taughannock Falls, the gorge deepens until you reach the wide amphitheater surrounding the main falls. The highest portion of the cliffs are Ithaca shale beginning about 25′ above the crest of the falls.  At that point the gorge is about 400′ deep.


The amphitheater surrounding the main Taughannock Falls is cut into a 150′ thick layer of Sherburne siltstone sandwiched between Ithaca shale on the rim and underlying dark Geneseo shale. – © Donna Mason-Spier (ref. # D075243)

You can get a good view of the falls from the footbridge over the creek, or you can continue a short distance to the last viewing area, but spray and mist often soak this spot.


Taughannock Falls: at 215′ the highest in New York State – © Donna Mason-Spier (ref. # D075238)

Yes, Taughannock is higher than Niagara, but of course it lacks the width and volume of water. (After all, Niagara drains the four upper Great Lakes on their way to Lake Ontario.) The highest water volumes are usually in early spring following snow-melt. Heavy summer storms can suddenly raise the water level and, in the past, have washed out portions of the trail.

Corrections, comments, and questions are always welcome at or connect through my Facebook page and photo page. For topics in the northeast, there is a separate community-type page at The Northeast Naturalist. Other northeast nature topics can be found on the parallel blog Northeast Naturalist.


Thunder Rocks in Allegany SP, NY — © Dave Spier

Allegany State Park, in the southwestern part of New York State, is unique to the area in never having been glaciated during the Wisconsin ice advance. The glacier stopped just short of the Allegheny River Valley that surrounds the park. Besides lacking the typical deposits of ground moraine, the park’s hills were spared the scouring effect of a bulldozing ice sheet.


“Snout-nose” is one of many rock creatures at Thunder Rocks. What animal does this one remind you of? A higher-resolution copy can be found on National Geographic’s Your Shot at

Thunder Rocks is one of several “rock cities” on hilltops near the Pennsylvania line. It is made of huge, joint-fractured Olean conglomerate blocks from the Pennsylvanian period, the same massive rock type that forms its more-famous cousin, Rock City, southwest of Olean. Other outcrops littering hilltops in the region come from different conglomerate layers in other geologic periods including the Mississippian Pocono group. West of Jamestown, the Wolf Creek conglomerate at the base of the late Devonian Conewango group forms Panama Rocks. All of the photos in this blog were taken at Thunder Rocks with the exception of the Salamanca conglomerate closeup. Higher-resolution copies of the first two photos can be found on National Geographic’s Your Shot here and here.



Conglomerate is essentially nature’s concrete. It contains numerous pebbles or even cobbles plus sand and silt cemented together by either limestone, iron oxide, silica or clay. It is sometimes called “puddingstone.” Conglomerates can occur in massive beds resistant to erosion. In the Allegany region, they are underlain with soft shales that easily erode and allow the conglomerate to break along joint planes. Soil creep then slowly carries the blocks downhill.


Olean conglomerate blocks from the Pennsylvanian period form Thunder Rocks. Note the cross-bedding in the middle layer.

Salamanca conglomerate, found chiefly at Bear Caves in Allegany SP and Little Rock City northwest of Salamanca, is from the late Devonian Conewango group.

Salamanca conglomerate, found chiefly at Bear Caves in Allegany SP and Little Rock City northwest of Salamanca, is from the late Devonian Conewango group. This closeup is part of a boulder at a parking area elsewhere in the park.

Maps and non-technical information on visiting Thunder Rocks can be found on the Enchanted Mountains – Cattaraugus County website. A separate page lists several other nearby sites on the Cattaraugus County Geology Trail. There is a brief mention of Thunder Rocks on page 173 in Roadside Geology of New York, by Bradford VanDiver, PhD, 1985/reprinted 2003, published by Mountain Press.


These photos were taken during the annual Allegany Nature Pilgrimage held the first weekend after Memorial Day. There’s usually at least one geology hike during the event. For most of these photos, camera white balance was set to “cloudy” for the overcast day, but light filtering through the spring canopy gives some scenes a slight greenish cast.

Corrections, comments, and questions are always welcome at or connect through my Facebook page and photo page. For topics in the northeast, there is a separate community-type page at The Northeast Naturalist. Other northeast nature topics can be found on the parallel blog Northeast Naturalist.

Thunder Rocks

Red Rock Park, NM


Red Rock Park, New Mexico — © Dave Spier

East of Gallup, New Mexico (USA), Interstate 40 passes along the south edge of the reddish Wingate Cliffs composed of Entrada Sandstone. About 2/3rds of the way from Gallup to Wingate, at exit 31, you can access Red Rock Park (originally a state park and now part of the Navajo Nation) nestled into the dissected edge of the cliffs on the west side of Rt. 566. The Entrada Formation is part of the San Rafael Group on the Colorado Plateau. It formed during the Late-Middle Jurassic from cross-bedded sand dunes in a Sahara-like environment around 160 (+/- 20) million years ago. The unit is named after Entrada Point in Emery County, Utah.


Massive Entrada Sandstone creates the Wingate Cliffs at Red Rock Park, New Mexico. (photos taken November 10, 2007) – © Dave Spier



In the vicinity of Red Rock Park, the lowest cliff layer was named the Iyanbito member which sits unconformably on top of the soft mudstones of the Triassic-age Owl Rock Member/Petrified Forest Member of the Chinle Formation underlying the valley eroded by the Puerco River and its tributaries. For a technical discussion with a map and rock columns, refer to USGS publication 1395d (1974).

It is unclear whether the Iyanbito has been renamed, but based on information on the New Mexico Bureau of Geology and Mineral Resources (NMBGMR) website, “The Entrada Sandstone [at Red Rock Park] is divided into two members… The Dewey Bridge Member consists of 40-60 ft of … reddish-orange silty sandstone and siltstone that form the base of the massive cliffs. The Slick Rock Member forms the spectacular cliffs and consists of 100-400 ft of reddish-orange well-cemented, thick-bedded, well-rounded sandstones, typical of ancient sand dunes. High-angle crossbeds or layers are seen in the sandstone. The sand dunes were cemented by silica and calcite from ground water and compacted to form the massive rock cliffs seen today.”


Cross-bedded sandstone layers deposited as sand dunes during the Jurassic Period around 160 mya are now exposed in the Wingate Cliffs at Red Rock Park, east of Gallup, New Mexico. – © Dave Spier


Church Rock at the head of a dry wash above the main campground at Red Rock Park, east of Gallup, New Mexico. Note the cross-bedded layer of Zuni Sandstone, near the bottom, dipping to the right (east) in this November sunrise photo. – © Dave Spier

Again from the NMBGMR, “The overlying Recapture Member consists of 100 ft of reddish-brown to brick-red siltstone interbedded with white to green to yellow sandstone … well exposed at the base of Navajo Church [Church Rock]… The Recapture Member was deposited in both [river] and [wind] sand-dune environments. The overlying Acoma Tongue of the Zuni Sandstone is the prominent [wind-deposited] sandstone with east-dipping cross­beds at the base of Church Rock (Anderson, 1993). The Jurassic Morrison Formation overlies the Acoma Tongue… The Salt Wash Member…is visible on some of the mesas north of the park and at the top of Navajo Church. This unit consists of 130-230 ft of red to orange sandstone with thin lenses of siltstone and shale… It was deposited in a [river] environment and is host to most of the uranium resources in the Gallup-Grants area.”

The Red Rock Park’s Jurassic deposits are overlain with younger Cretaceous rocks which form high ridges north of the park.


Roadside Geology of New Mexico, by Halka Chronic (© 1987/reprinted 2005), published by Mountain Press

The Iyanbito Member  (A New Stratigraphic Unit) of the Jurassic Entrada Sandstone, Gallup-Grants Area, New Mexico, by Morris Green, 1974, USGS  publication 1395d at

New Mexico Bureau of Geology and Mineral Resources Geologic Tour: based on the following:

Lucas, S.G., Heckert, A.B., Berglof, W.R., Kues, B.S., Crumpler, L.S., Aubele, J.C., McLemore, V.T., Owen, D.E., and Semken, S.C., 2003, Second-day road log from Gallup to Fort Wingate, Sixmile Canyon, Ciniza, Red Rock Park, Church Rock, White Mesa, Thoreau, and Grants, New Mexico Geological Society Guidebook 54, p. 35-68.

McLemore, V.T., 1989, Red Rock State Park: New Mexico Geology, v. 11, no. 2, p. 34-37


Cliff Swallow nests (on the cliff!) at Red Rock Park, New Mexico, November 10, 2007. © Dave Spier


Eurasian Collared-dove (Streptopelia decaocto) at Red Rock Park, New Mexico, in the campground trees, November 10, 2007. © Dave Spier

If you’re a geologist or geology buff familiar with the park, please comment or contact us. Corrections, comments and questions are always welcome at or connect through my Facebook photo page or my personal page, Dave Spier (northeast naturalist). Other outdoor topics can be found on the parallel blogs and


Campground at Red Rock Park, New Mexico, November 10, 2007. © Dave Spier

Green Lakes State Park, NY

Live and dead Northern White-cedars line the shore and shadow the reef at Green Lakes SP, NY. (lens: 17-40mm at 27 mm + polarizer on full-frame body; exp. 1/80 to stop the ripples at f/6.3, ISO 200) D078462 uncropped – © Dave Spier

Green Lakes State Park, NY — © Dave Spier

Donna and I were at Green Lakes State Park east of Syracuse, NY on Sunday (Labor Day weekend) and spent some time walking the lake trail on the east side and photographing the marl reefs. These are “microbialites” made by living organisms, in this case cyanobacteria that bind calcium carbonate from the dissolved limestone.

Deadman’s Point is the largest reef in Green Lake, and it’s partly exposed when water levels are low. It began thousands of years ago and continues to grow as cyanobacteria precipitate more calcium carbonate dissolved from the limestone and related dolostone in the surrounding hills. Algae, mosses, freshwater sponges and fallen trees add to the reefs and slowly become encrusted.

Deadman’s Point (17-40mm at 24 mm + polarizer on full-frame body; exp. 1/30, f/22, ISO 400) D078451 uncropped – © Dave Spier

The shoreline is dominated by Northern White-cedar trees (Thuja occidentalis), better known as arborvitae, which love alkaline limestone soils. At Deadman’s Point, these trees are 200 years old. The surrounding hills help protect the trees from stong winds.

For a longer hike, you can add the Round Lake trail to the west. Along with the adjoing 59-acre old-growth forest, it’s now designated as a National Natural Landmark. The tallest tree is 147 feet high.

Round Lake is 34 acres and 170 feet deep while Green Lake is 65 acres and 195 feet deep, so the top and bottom layers of water almost never mix, an unusual condition called “meromixis.” The cold bottom layers have a higher density due to salinity from Silurian salt deposits in the local rock layers. The warm surface layer has a lower density and tends to just float on top. In addition, both lakes are nestled in basins that protect them from strong winds that would initiate mixing. Green Lake was the first meromictic lake identified in North America, so it’s also the most studied.

Two sunfish hide in the shadow of white-cedar that fell over the reef around Green Lake. (lens: 18-55mm at 55mm on digital Rebel; exp. 1/13, f/5.6 at ISO 100; auto WB) D006570 cropped to 3072×1615 before resizing — © Dave Spier

As I recall, Round and Green Lakes are pro-glacial plunge pools cut by rivers pouring off the top of the receding ice sheet at the end of the last Ice Age. The deep water below 55 feet is devoid of oxygen so sediments and organic matter are well-preserved on the bottom and can be studied to see how vegetation and the climate have changed since the end of the Ice Age.

I like maps, but if you’re more comfortable with GPS, the USGS coordinates for the park are 43.0513738 N and -75.9658865 W. The eBird-hotspot coordinates for Green Lake are 43.0493361, -75.9646249. For a general overview of the park, visit

Corrections, comments and questions are always welcome at Also you can connect through my Facebook photo page at Dave Spier (photographic naturalist) or my personal page, Dave Spier (northeast naturalist).

Painted Desert Geology

To set the stage, you’re facing northwest and looking at Pilot Rock, elevation 6234 feet, across the Painted Desert from Chinde Point in the northern portion of Petrified Forest NP, Arizona. Note the late Cenozoic lava flow at the lower right. (November, 2007 photo © Donna Mason-Spier)

Painted Desert Geology – Part 1, Northern Petrified Forest NP, AZ — © Dave Spier

From east of the Grand Canyon, the Painted Desert crosses the Colorado Plateau in a long curving arc southeastward to encompass the Petrified Forest east of Holbrook, Arizona, and then continues into New Mexico and northeastern Arizona. The bright colors, primarily shades of red, are due to iron oxides in the late Triassic Chinle formation deposited as clay, silt and sand in lakes and wetlands that covered a broad plain over 200 million years ago (mya). Most of these sediments are now soft mudstones and related rocks with a few harder layers of sandstone. Color contrast in the northern section of the Petrified Forest is provided by a light-colored band of volcanic ash known as the Black Forest bed.

The bright-colored layer on top of the low hills is volcanic ash in the Black Forest Bed, named for the unusually-dark tree trunks it contains. In the foreground, we are standing on basalt lava of the Bidahochi Formation exposed at the rim of a mesa overlooking the Painted Desert north of Kachina Point in Petrified Forest NP, AZ.
(23mm/full-frame photo © Dave Spier)

Bentonite clay layers are formed from the volcanic ash of the Black Forest bed and provides contrast in the Chinle Formation seen from Kachina Point using a 300mm telephoto. (© Dave Spier)

On top of the Chinle layers there are younger deposits of clay, silt and sand plus lava flows belonging to the Bidahochi Formation, much of which has been removed by erosion. These Tertiary layers can be seen from several of the overlooks north of I-40. Flat-topped mesas to the north are capped by this formation.

The buff-colored band at top is assigned to the Bidahochi Formation and was deposited in a lake around 50 million years ago [per Dr. Sydney Ash] during the Tertiary Period. The red layers below it are the colorful and much older Chinle Formation. (November photo © Donna Mason-Spier)

Photography Notes: On cloudy days, the diffuse lighting makes topographic features look flat and featureless. If possible wait for a sunny day or time and choose locations where the sun will be to your side (left or right). This side-lighting creates shadows for contrast and brings out the texture and details. The effect is maximized soon after sunrise and before sunset, which are the golden times of daylight and give the warmest color tones.

Painted Desert from the overlook between Tiponi and Tawa Points, taken at noon on a cloudy day. (© Donna Mason-Spier)

We were on our way to the Grand Canyon, so time constraints reduced our ability to revisit this section under better lighting conditions. There is no campground [or car camping] in the park, [although you can backpack which requires a permit], and the extra travel further reduced time for photography.

Painted Desert from Tawa Point using a 300mm telephoto on Canon XT; even with the sun out, mid-day lighting tends to be flat without strong sidelighting. (November 10, 2007 photo © Dave Spier)

 Corrections, comments and questions are always welcome at or connect through Facebook (Dave Spier, photographic naturalist and northeast naturalist).

Raven flying by Tiponi Point around noon – © Dave Spier


Petrified Forest – a Story in Stone, by Dr. Sidney Ash (© 2005), by Petrified Forest Museum Association

Roadside Geology of Arizona, by Halka Chronic (© 1983/reprinted 2002), published by Mountain Press

Petrified Wood

Petrified wood is actually a fossilized replica of the original tree, sometimes down to such minute detail that the original cells and wood-grain can still be seen. It’s formed by the gradual replacement of organic matter with agate when hot, silica-bearing water percolates down through the rock layers containing the buried logs. The silica comes from volcanic ash deposited after the trees died. Incomplete mineralization allows the woody structure to remain visible.

Agate is a cryptocrystalline form of quartz, meaning the crystals are so microspcopic that they are hidden. Chalcedony is a more general term for micro-crystalline quartz that includes agate plus the minerals carnelian, chrysoprase, onyx, and sardonyx.

Quartz is a common mineral and the word usually implies the crystalline form of silica, or silicon dioxide, written chemically as SiO2. Colored varieties of quartz are due to impurities. Red, orange and tan are usually due to iron. Manganese and carbon add other colors, while chromium in rare instances can add green

Petrified Forest National Park, Arizona

Sections of petrified logs are naturally scattered on the ground. Donna is in the background photographing a log on a “pedestal,” which can be seen in the next photo below. (photo © Dave Spier)

Donna’s photo of a petrified log segment on a pedestal
protected from erosion by the log (photo © Donna Mason-Spier)

One of the most famous places to see petrified wood is the Late Triassic paleo-ecosystem preserved in the Chinle Formation at Petrified Forest National Park straddling I-40 east of Holbrook, Arizona. The National Park Service has an offical website  and a map.  The petrified forests in the park were actually log jams on a river that flowed through Arizona during the Late Triasic period over 200 million years ago. Isotopic dates range from 211 mya in the Black Forest Bed to 218 mya in the older Blue Mesa layer.

Petrified Wood

The trees at that time were conifers, gingkos and tree ferns. So far a dozen species have been described. The area was likely near the equator at the time and the trees grew continuously without marked rings caused by seasons. When they died, some of the trees could have been approaching a height of 200 feet.

Petrified log segments on a slope and they even look like wood…
(photo taken with polarizer on 17mm wideangle at f/22 on full-frame digital body, 11/11/07 — © Dave Spier)

Corrections, comments and questions are always welcome at Related topics can be found on the parallel blogs and Also, you can connect through my Facebook photo page at Dave Spier (photographic naturalist) or my personal page, Dave Spier (northeast naturalist).

one final, new link: