Often, folks will ask me the question for which this post is named.  As I was thinking about what to write for this edition, favorite sites came into my mind.  These sites are neat to visit because they have their own identity and represent different episodes of our Earth and history. Not placed in any order, here we go!

Let’s start by traveling south of U.S. Rte. 15 out of Gettysburg.  After bypassing all of the neat history there (and geology), we cross over the Mason-Dixon Line into Maryland.  Travel past Thurmont and if you can hold off the temptation of stopping at Mountaingate Restaurant for a bite to eat, wait, until your return trip home.  Just a short piece down Rte. 15 you will see a sign at the next exit for Catoctin Furnace.  With the many times I traveled this route, I was amazed when I finally got there 2 years just how close it sits to the highway.  In fact, before getting to the exit, you will travel under a footbridge that looks slightly out of place.  The footbridge is there to allow people parking at the Catoctin Mountain Park Visitors Center an opportunity to walk to the furnace site.

The Catoctin Furnace Portal and Stack near Thurmont, MD

Catoctin Furnace has quite a history. A historical marker at the furnace reads, “Catoctin Furnace: An important iron furnace during the Revolutionary owned by Governor Thomas Johnson and his brothers.  Furnished 100 tons of shells used at Yorktown.”  A local hematite iron deposit was discovered in the 1770’s by Thomas Johnson, Jr., who later became governor of Maryland.  One historical account names James and Thomas Johnson as the builders, another account mentions Thomas Baker and Roger Johnson and a later account mentions a Baker Johnson as a later owner. The first furnace sitting here was the Johnson Furnace which was a cold-blast operation working from  about 1776 to 1795 and then was idle until 1803.

An existing wall of the Ironmaster’s house

The furnace was in operation again from 1803 until 1811 with substantial improvements.  Early production consisted of household implements, tools and cast iron stoves.  The works were purchased by John Brien in 1831 and modernized. The Johnson Furnace operated until it was shut down and dismantled in 1890.  The site of the Johnson Furnace was probably in about the middle of the retaining wall behind the existing stack.

Another owner built the Isabella (also referred to as the Catoctin) Furnace in 1856. The Isabella Furnace was supplied with a steam-powered hot-blast mechanism.  The Isabella Furnace was a rather advancement design for a charcoal furnace.  IT might have been designed to use anthracite coal or coke, but neither were available.  The Isabella stack is what remains today.

A display board at Catoctin Furnace showing the historical and existing structures

In the late 1880’s, when the furnace was at its peak, the complex consisted of 80 houses for workers, a saw mill, a grist mill, company store, farms, an ore railroad, and  the stacks.  A magnetite mine on a hill to the southwest supplied the iron ore for the Isabella Furnace.  The furnace closed in 1903, but the magnetite mine continued operating until 1912, supplying ore to a Pennsylvania furnace.

Today, the complex shows the wear and tear of historical structures, but one can get a great idea how a furnace operated, the required materials and facilities needed to produce iron products.  Walk the trail, which is a self-guided trail and see the walls of the ironmaster’s house; the pond and race that supplied the water to turn the waterwheel, slag piles and ruins of other buildings.  A brochure is available for download at http://www/dnr.statre.md.us/publiclands/cunninghamhistory.html,

Ok, let’s shift gears and head into a different region, up north to the world-famous anthracite coal region.  Every time I travel into that region and see the miles of coal dumps and abandoned pits, it amazes me just how much history there is.  Some of the best anthracite coal ever known came out of this region and thousands of articles and books have been penned telling the stories about miners, companies, the good and the bad of the industry and its future.  If you find your way to Hegins, SchulykillCounty and follow Pa. Rte. 25 west toward Shamokin, you will continuously pass old mines and large coal dumps.  After going over the mountain and dropping down toward Shamokin, turn left onto Bear Valley Road.  Follow Bear Valley Road to its dead end (or at least as far as you can travel without getting stuck).  Watch for signs that the road is no longer maintained and travel at your own risk., O My!!!

From where you park the car, walk up the “road a short distance to where you are on flat ground.  There is a large, tall dump pile on your right and the terrain seems to drop off to the left.  There is a well developed trail, mostly worn by 4-wheelers, that leads down the hill.  Follow this trail for about 300 yards and suddenly you will find yourself in a long abandoned coal pit.  In front of you is a mound that looks like a whaleback.  In fact, that is this nick named for the location.  The whaleback is composed of rock that has been pushed up in to an arch shape fold known to geologists as an anticline.  Take your eyes to the left end of the whaleback and notice where it disappears into the high vertical wall.  Look at the rock above the whaleback, the rock there is folded downwards into a structure known as a syncline.  Wait, we aren’t quite done yet.  Look at the far wall of the pit.  It appears as if it is curved and smooth.  That wall is actually one-half of an anticline coming down beside the whale back.

View of the Whaleback looking west from the overlook.

You think that is confusing, it is?  This is one of the best examples of folding of rocks in the United States.  Visualizing the forces that formed these folds and the stress and pressure involved is overwhelming.  These features are clear cut proof of the mountain-building processes that formed the Appalachian Mountains when Africa and North America came together about 340 million years ago.

Look closer at the rock and you may spot some petrified wood and fern fossils in the shale.  The rock formed during the Pennsylvanian Period tells us the story of a time when this area was an “Everglades” environment with abundant vegetation and slowly forming what would become the famous coal region.  The coal was originally bituminous but with the continental collision the coal was metamorphosed into anthracite.  You can see some of the coal veins on the wall containing the syncline.

It is recommended not to walk on the whaleback.  The rock is slippery and gets more dangerous when wet.  Also, there is a lot of loose rock on the surface that could give way when you step on it.  Enjoy this great location but use caution.

As guess when one gets older, you begin to look back into the past and get a little smile on your face when you think for locations you used to visit as a child.  Remembering those days brings back memories, both good and bad, but today these are what keeps us young at heart.  I am not calling myself old but I have been studying local geology for over 30 years and wonder what my more my mental “PC” will hold.  I would like to look back at several of those memories and relate it to geology.  Remember, as I said in an earlier blog, one can relate anything to geology if you know care to.

My first stop on my memory walk is Camp Michaux Church Camp in Michaux State Forest and close to Pine Grove Furnace.  Located within South mountain (the northern extension of the famous Blue Ridge mountains of Virginia, North Carolina and Tennessee, its geology is quite diverse.  Did I know that when I attended church camp in the mid to late 1960’s?  The answer is no.  In fact, going to church camp was one of the hardest things for me to do in my early life.  I hated church camp because I was being forced to meet new people my age and had to spend a week away from my home, family and my pet dog, Lassie.  While standing at the administration building of Camp Michaux early in the week, I often looked at the distance and wondered just how many more times I would be looking at that high mountain that week before my parents would arrive on Saturday morning and get me out of this place!!!!

Pole Steeple located near Laurel Lake is a large outcrop of quartzite

Little did I know what was in that ridge. The mountain was on the opposite side of the valley from the camp.  I later discovered that a favorite scenic overlook for many hikers was located on that ridge.  The site known as Pole Steeple is a fabulous exposure of quartzite.  Two towers of this metamorphic rock stand over 70 feet in height above the hillside. From the top of the tower, you are able to see the parallel ridges of South Mountain and the valley far below you where Pine Grove Furnace and Laurel Lake are found.  What a view, especially at this time of year with the changing colors of the foliage.  Although it is about a 0.75 mile walk up from the parking lot found behind Laurel Lake, it is well worth the walk up.  Unfortunately, the further into the hike you get, the steeper the terrain becomes.  The last little bit to the top of the towers requires you to climb natural steps of quartzite between the “twin towers.”  Actually this access to the top is in a fault, a natural crack in the quartzite where movement took place many millions of years ago during the time that South Mountain was pushed some 50 miles to the northwest by an intruding African continental plate.

Pine Grove Furnace as it appears today.

Right down the road from Camp Michaux is Pine Grove Furnace.  What a great place to visit not only to recreate but also to learn how a 19^th century iron-producing community survived and iron was produced.  Right there, everything you needed to operate a blast furnace is found – iron ore, limestone to act as a flux to separate the impurities and chestnut trees that produced great charcoal for the heat of the operation.  The great lake to take a summer dip is Fuller Lake and was the location of the iron mine.  Believed to have been about 80 feet deep during the mining era, workers dug the iron ore out by pick, shovel and black powder.  The ore was limonite and contained about 43% iron, not a bad percentage for those days.  Look around the complex!  Uphill from the furnace and its interpretive signs is the store, Iron Master’s House, the stable and company office.   All have been preserved by the State Parks and are often available for a tour.

A section of the Ironmaster’s house at Pine Grove Furnace

Behind Fuller Lake and just where you think you are going back into the dark wilderness of Michaux State Forest, you come upon “salt-box looking cabins scattered throughout the forest.  These structures are what remains of the workers dwellings.  There was no need to take a bus to work or carpool.  You walk a short distance to work,  One can use their imagination here by seeing the valley full of smoke from the tenant houses chimneys, the sound of the furnace in blast and the sound of workers removing the limonite from the ground.

Actually my second memory is another camp where like Camp Michaux.  My homesickness also prevailed at Camp Tuckahoe Boy Scout Camp near Dillsburg.  It was a bit more easy at boy scout camp, at least I was with guys who I knew.  Matter of fact, my father spent a number of summers working at Camp Tuckahoe also.   Likewise as Camp Michaux, Camp Tuckahoe is located within South Mountain, just a bit further north.   If I would have known what I know now about the boy scout property, my stay there would have been a nicer experience. When learning about local geology, I quickly learned that the highest point in York County is found on the boy scout camp property.  At an elevation of 1360 feet, Stone Head overlooks the Piedmont to the east and south.  Does the rock appear as a head of a human?  Well, let’s say kinda.

Some 10 or so years after my last camping experiences at Camp Tuckahoe, I learned that Dogwood Hollow contains a wealth of mining history.  Dogwood Hollow is where Tuckahoe Road runs from civilization back to the camp entrance.  About 6 different iron and clay operations worked on the slopes of the hollow from the mid 1800’s up into the 1920’s.  Similar to Pine Grove Furnace, a old-time mining village existed here.  Even today as one drives back the much improved road compared to what it was like in the 1970’s and 1980’s, one can spot occasional foundations of houses and buildings all related to these mining operations.  Even a look at an area topographic map shows trenches and ponds on the north side of Dogwood Hollow where limonite ore and white clays were removed.  Digging alittle deeper in the history books, a rather unique G-gauge railroad transported the ore and clay out of the mountain to Beavertown, just north of U.S. Rte. 15.  From here the material was transported by rail to points outside of the area.  Wow, all of that history was under my feet while a scout at Camp Tuckahoe.

My last thoughts about going down memory lane is one that is hard to relate to geology.  I have always loved auto racing as a boy.  Before I could drive a car, my mother would take me to Lincoln Speedway located just west of Abbottstown off of U.S. Route 30.  Unfortunately for me, my mother would only take me maybe once a month, not nearly as much as I desired to go, believe me.  I remember even with all of the noise produced by these powerful racing machines streaking around a dirt oval, my mother would sit there and sleep while I routed my favorite race driver on to victory (or at least I hoped).

Clay is being screened at the Magnesita Company quarry in West York preparing for delivery to LIncoln Speedway.

Well, today I act as a clay consultant at Lincoln Speedway.  Believe some times while standing down along side of the race track during a Saturday night racing program, I look up into the grandstands, which have only be modernized slightly, and think about those wonderful nights that my mother endured for me to enjoy what has become a big part of my life.  So what does a clay consultant do.  Almost every year, the management of Lincoln Speedway entrust me in locating what I would consider the best racing clay to put on the track.  It is a big responsibility as I have faith that the clay we are putting down on the track will be safe, but yet competitive for race drivers, some of which are traveling over 100 miles per hour.  I get to check the clay during an evening of racing to test its moisture and compaction.  The best part of this “fun” job is interacting with the others that work there as well as some race fans I have had the privilege to meet.

Fred Putney considered to be one of the best track preparers in the country, grades out the new clay at Lincoln Speedway.

One of the showcase pieces of our southeastern Pennsylvania landscape is the Susquehanna River. Not only is this the largest body of water in our region, it also provides us with some scenic views that have been drawn by artists and captured by photographers for many years. 

But before we get into some particulars about the river itself, let’s look at some general facts. First of all, the original spelling was “Sasquesahonough” and named for the Indians that called the river valley its home. Can anyone guess where the headwaters of the Susquehanna River are located? I discovered the answer myself by accident in the 1980s. Returning home on a trip to a world-famous mineral collecting site, I passed a historic marker stating that this location was the starting point of the river. 

My reaction was “wow.” 

The Susquehanna River is actually better known for a sports attraction — the National Baseball Hall of Fame in Cooperstown, N.Y. Lake Ostego in Cooperstown is where the water starts its journey southward. The main branch and the west branch of the Susquehanna drain a total of 444 miles to the Chesapeake Bay, draining a total of 27,500 square miles. This makes the “Susky” the longest river on the East Coast and the 6th-longest non-commercialized river in the world.

That’s another “wow.”

Topographic map of the Susqueahanna River through the Applachian Mountains

When rivers are developing their original flow across a landscape, the water obeys one principle: It wants the easiest route possible with no resistance. In other words, the water doesn’t want to work for a living. When one imagines the landscapes surrounding the Susquehanna River, there are many ridges and hard rocks that the water currents cut through. For example, picture the drive from Harrisburg north to Selingsgrove, a trip through part of the Appalachian Mountains. If you examine an aerial photograph of the area, you will find that most of the gaps you travel through on your drive are actually the same ridge that was bent by great tectonic forces millions of years ago. Only as you get close to Selingsgrove does that ridge not traverse the river.

View of the river from Pinnacle Rock in Lancaster County

The amount of rock and dirt removed from one of the water gaps is mind-boggling. I did a quick calculation on the amount of material removed from the water gap between Hellam Point in York County and Chickies Rock in Lancaster County for a recent program. I estimated over 349 million cubic yards of rock and dirt carved out by the Susky. That number alone is hard to imagine; now, think about the number of water gaps along the route of the entire river! 

These water gaps are awesome. Think about how much material has been carried into the Chesapeake Bay and the Atlantic Ocean thanks to erosion.  Near Bainbridge and Perryville, Md., there are exposures of sediment deposited by the river that are about 30 feet high.  The Susquehanna River has been nationally recognized for its water gaps and has attracted college students from across the country.

The Susquehanna River from Shull’s Rock York County looking north toward York Haven

Just how old is the Susquehanna River? The answer has been debated since the beginning of modern science. Some scientists believe that the river was in place prior to the formation of the Appalachian Mountains some 340 million years ago. If that were the case, the river would have been flowing in the opposite direction because the highlands were located to our east and the ocean was migrating to the west. If it were formed after the great collision between Africa and North America and the supercontinent Pangaea, the Susquehanna River would have flowed in its current direction.

It is mentioned in the classic “Geology of Pennsylvania,” published by the Pennsylvania Geologic Survey and the Pittsburgh Geologic Society in 1999, that the Conewago Member of the New Oxford formation in York County was formed by the Susquehanna River. That rock unit is about 210 million years old and forms the Conewago Mountain north and east of Dover.

Quartz pebbles found along Cherry Hill Road

If one were to write a book about the history of the great river, the largest chapter would concentrate on the Ice Age period, between 100,000 and 10,000 years ago. Yes, it is true that glaciers did not cover any of York County. In fact, the closest wall of ice was located about 50 miles to the north of Harrisburg. However, during this time, with oscillating periods of warm and cold weather, the ice would retreat and advance with change. When the mile-high wall of ice would melt during the warmer intervals, additional water would be sent down the river valley. Additional water would increase rates of erosion and downcutting. It was during this time that great downcutting occurred through our crust in Pennsylvania. Earlier geologic works have mapped some of these river terraces, which indicate a previous location of the river. Some of these terraces are 300 feet above the Susquehanna River’s current elevation. For example, along Cherry Hill Road in southern Lancaster County on a hill about a mile from where the river flows now, there are water-worn quartz pebbles marking one of these terraces.

Cross section of the Susquehanna River from Harrisburg south to the Chesapeake Bay

Holtwood Dam

To examine the forces that the Susquehanna River has placed on soft and hard rocks in our crust, travel to what is called the “Deeps,” south of the Holtwood Dam. Park at the Lock 12 Holtwood Dam parking area and walk south on the trail. After passing the restored Lock 12 and the heavily overgrown Lock 13 under the Norman Wood Bridge, you’ll find yourself out on the island. Here you can see and hear the forces of water hitting upon the metamorphic rocks. Look for places where the rock has been carved away, the formation of potholes, and channeling. This is a wonderful place to go to have a picnic lunch and admire the beauty of one of the most famous sections of the Susquehanna River.

The “Deeps” south of Holtwood Dam

Lock 12 at Holtwood Dam

The rapid downcutting of the Susquehanna River during the Ice Age affected the tributaries flowing into the river. These tributaries did not have additional water flowing in their channels to increase their erosion. The end result was that the tributaries were not able to keep up with the downcuttting of the river, thus resulting in what geologists call a “reverse” profile of these tributaries.

Normally, the steepest section of a stream would be at the headwaters and the channel would become flatter as it came closer to the river. Not the case here. The tributary is steeper closer to the river, resulting in scenic waterfalls near the junction of the Susky. Locations such as Wildcat Falls, Accomac Gorge and Otter Creek in York County and Tucquan Glen and Shenks Ferry in Lancaster County are great representatives of such a case.

A waterfall at Accomac Gorge

I have touched on only a few of the outstanding features of the Susquehanna River here.  One of the field trips I’ve designed and conducted for groups is a tour around the river between Columbia and Holtwood Dam. Drive River Road in Lancaster County to Holtwood Dam, cross the Norman Wood Bridge and travel up Pa. Rte. 74 and Pa. Rte. 425 to Indian Steps to explore the river and its hills.  Much human history (prehistoric, historic and industrial) is found around every turn of the road.

Ok, for you David Letterman fans, here comes the Top Three Rock Exposures in York County!  Whoever cared about this category anyway?  I know someone who would respond “It is only a stupid rock, who cares?”  Yes, it is only a rock, but as you find out, these exposures have played a part of our local culture and provides us some information about our past.

Number 1 on the list is Indian Rock located in York Township along the Codorus Creek at the base of Indian Rock Dam.  Um, I wonder if the name of the dam had anything to do with Indian Rock.  In that case how about the naming of Indian Rock Dam Road, Indian Rock Elementary School or Indian Rock Campground?  This outcrop wasp icked as my favorite because of its significance to the area and it carries with it one of my favorite stories in my geologic experience.   As one who has learned about the geology of York County through research and reading of historic geologic reports, a picture of an exposure on a floodplain from George Stose and Anna Jonas’s 1939 classic report on the geology of York County keep coming into my mind.  I had never found this site, although their brief description states it is a quartzitic rock outcrop was located one mile north of Brillhart Station.  According to these two geologists, this outcrop is the remnant of an anticline (arch-shaped fold).

Indian Rock looking to the east (Jonas and Stose, 1939)

Ok, so I put the outcrop on my bucket list with intensions to locate this exposure in my spare time.  I didn’t have to wait for a free moment.  A photograph of a swimming hole around the Codorus Creek with a whale-back shaped rock outcrop named “Indian Rock” in the York Dispatch’s “Around Town” column by legendary writer Harry McLaughlin, asking if anyone knew its location.  Wait a moment, I should know where such an exposure is, but I didn’t.  I got my wife, Lou Ann out of bed early the next morning and told her, we are going to solve a mystery.  We both like to solve such puzzles, particularly when it involves geology or local history.  So off we go with the only clue of the Stose and Jonas picture and the “Around Town” photograph in hand.  We stop at the Indian Rock Dam office and inquiry.  No help there.  We go to Indian Rock Campground and guess what, no help there.  Geez, doesn’t anyone look at rocks?

We stop at a private residence on Indian Rock Dam Road near the railroad tracks and after showing them the newspaper article, the owner replies “There is a rock back behind the house, but not sure if it is the one.”  Great news and with permission we walk through the woods paralleling the Codorus Creek and guess what?  This magnificent rock rose right out of the floodplain.  What a strange place for an exposure.  No other rocks in sight and we have this 60-foot long, 15-foot high piece of Earth’s crust.  We verify this is the locality both in the postcard.  After inspecting the quartzite outcrop identical to what was described by Stose and Jonas, we discovered the only way to take a picture of this locality was from the other side of the stream, back on Indian Rock Dam property.

Indian Rock as seen from the west side of the Codorus Creek

Off we go with smiles on our faces as we returned to the property where we started.  Continuing our conversation with the staff of the flood protection structure for York, we told them we found it and guess where it is, at the base of your spillway.  Granting us permission to walk down the hill to the stream, we got the picture we were seeking.  Harry McLaughlin was happy to receive the picture from us commenting “I knew you could do it.”

What makes Indian Rock so cool to geologists is the fact that this “whaleback” sticks out because all of the surrounding softer rock has been weathered and eroded away.  Quartzite is rather durable to the climate compared to the surrounding rock.  Also, Indian Rock is the core of an anticline and shows just how much the rocks in this portion of York County has been through with two crustal collisions and the rifting apart of a continent.

#2 on the list is the Accomac roadcut in Hellam Township.  For those traveling to the popular Accomac Inn for dinner, this is the roadcut you see on the right-hand of the road just before arriving to your destination.  What makes Accomac just interesting?  It is one of the few sites (and certainly the best) where you can find volcanic rocks.  One of the most common questions I receive is “Were there volcanoes in York County?”  Right here is the proof.  Exposed here is a rock known as a metabasalt.  Basalt is a volcanic rock composed of dark-colored minerals and has its origin on  the ocean bottom.  “Meta” has been added in front of “basalt” since the rock has been through several periods of heat and pressure with our geologic history.

The Accomac roadcut looking east

The rock here is a greenish color due to the presence of chlorite and small amounts of epidote.  Look carefully and you will see rounded quartz pods (some up to 12-inches across).  These were gas bubbles in the lava which eventually broke and later filled in with quartz, chlorite, epidote and a trace of copper.  That’s right, I said copper!!  Copper frequently forms in a volcanic setting such as this.  In fact, the same rock is exposed in larger amounts in South Mountain near Greenstone, Iron Springs and New Hope, Adams County.  Mineable copper deposits were worked in this area in the 1800’s into the 1920’s.

If you walk toward the west end of the roadcut, look for yellowish-green veins cutting through the metabasalt. This is antigorite, a serpentine mineral.  Nice hand specimens can be easily collected here.

Antigorite in metabasalt from Accomac

When you collect your specimen of metabasalt, remember how this rock was formed about 600 million years ago.  This was what geologists called a divergent boundary where two crustal plates were moving apart.   Today’s Mid Atlantic Ridge would be a good example of what Accomac looked like as a continent was tearing apart in the Precambrian Era.

For a bonus by stopping at Accomac, carefully cross the road and look at the beautiful waterfalls.  The water is flowing over metabasalt.  Notice the potholes and the wearing away of the rock by the stream erosion.

Potholes in the stream at Accomac

Location #3 has been talked about in this blog before but is worth talking about because of its accessibility and geology.  This is the Rossville roadcuts just north of this small town in Warrington Township.  Traveling north of Old York Road, the first roadcut on the right is diabase, an igneous rock that was magma but cooled into a rock deep beneath the surface.  Because of the slower cooling than compared to the magma on the surface (lava), the magma cooled slower forming larger crystals.  Here the rock is called coarse-grained.  You will notice several drill holes in the rock.  These were made by one or more geologists who conducted research on diabase in Pennsylvania.

My Messiah College Earth Science class interpreting the diabase outcrop

Look at the cracks in the rock or on some of the loose diabase laying at the bottom of the hill.  You might be lucky to find some white radiating crystals belonging to the mineral stilbite.  If you find small cavities in the stilbite veins, use a microscope or hand lens to try to spot small “cubic” crystals.  The minerals heulandites and chabazite are also found here.  Although not economically valuable, these are nice minerals to collect.  Water flowing through the cracks and the rock have formed this minerals.

Traveling up the road to just over the crest of hill, you cannot miss a large hole in the roadcut.  The rock here has changed from the first roadcut.  This rock was originally sedimentary in origin but when the magma intruded up through these sedimentary rocks, the heat baked them into a metamorphic rock known as a hornfel.  Various minerals form as a result of this reaction between the chemistry of the sedimentary and magma.  Garnet, epidote and actinolite are common here.  Since the construction of Old York Road in 1974, people have been collecting azurite (blue) and malachite (green) here.  These are two copper minerals are only found on the outside of the rock so there is little use to break them open.  However, using a special microscope, one could detect small  blebs  of native copper inside the rock.

Azurute and malachite at Rossville

If you go here to collect, it is recommended to take along a rake.  Because it is difficult and dangerous to work in the hole to extract the copper-bearing hornfel, smaller pieces of azurite and malachite can be found on the talus pile leading up to the hole.  Only two weeks ago, I found a colorful piece recently dug out by an earlier mineral collector.

My Continuing Education students from HACC search for copper minerals at Rossville

You want to try something different?  Travel to the copper hole after dark with a battery-powered black light.  Opal hyalite is found on the edges of some of these hornfels and under a black light it illuminates a pale green.  Opal is formed by water through and around the rock creating what is called a secondary mineral.

Finally, several years ago while I was visiting the copper hole on my way home from another project, a was approached by an older gentleman who seemed interested in why the hole was in the road cut.  After chatting with him for several minutes about the azurite and malachite, I learned I was speaking to former Pennsylvania governor,  George Leader.  He owns a farm near Rossville and was always curious about the attraction to this location.  Sometimes you just never know who you might talk to when you out and about, but it is always interesting.

If asked what the No. 1 spectator sport in the world is, could you answer the question?

The answer is looking at rocks. Can’t figure it out? Think about the number of people who visit attractions where rocks are seen. Sites including the Grand Canyon, Niagara Falls, Devil’s Tower, Yosemite National Park and Meteor Crater come to my mind quickly. Millions of people enjoy vacations where rocks are visible and, yes, maybe I am exaggerating a bit, but it is true. On a much smaller scale is the York County Heritage Rail Trail, where more than 300,000 park users enjoy the 22-mile corridor every year. Do people come out to the trail to view the rocks? To be honest, I doubt it, but many users soak in the beauty of the trail which includes the rock outcrops.

Compared to spectacular, massive rock exposures in southwestern United States, York County supports only small rock outcrops, unless you are in the area of one of our quarries.  This makes interpreting the geology of the area a bit more complicated.