So what can I find in York County?
It has been a while since I wrote a blog entry, but things got pretty hectic around here this spring. I was approached in mid-December by Messiah College to teach an evening Earth and Space Science course for students. Wow, it was an eye-opener — not only learning the system at Messiah but also catching up on the technology of teaching. It had been more than 20 years since I taught a college course, and things had changed. Although I met some challenges with creating labs, I had a great time relating to the students. We even went panning for gold near the school on our last lab night together and found nine flakes.
Partial trilobite fossil from Locust Lane
In any event, one of the most common questions that come my way is, “Where can I take my son (or daughter) rock-collecting without driving too far?” I always enjoy helping anyone out, but when I see a chance for a family to become closer-knit over a common activity like rock-hounding, I want to load them into the car and go.
Below are some of the local finds. Remember, exploring road cuts is the easiest place to collect, but keep in mind how busy a road with traffic can be. Stopping on interstates is not a good idea, as state police disapprove of rockhounding there. Chances are, minutes after you get out of the car along the interstate, an official will be there to chase you away. Also, some rockhounding destinations are on private property, where you’ll need permission to access the area. As I may have said before, we spend 80 percent of our time convincing property owners to let us onto their land.
Let’s take a look at some of the more outstanding finds, starting with the northern section of York County. From Shiloh north to Dillsburg traveling on Route 74, or from Emigsville to Reeser’s Summit going north on Interstate 83, you have a region where rocks formed 210 to 160 million years ago, mostly in an Everglades-type of environment. These “redbeds,” as they sometimes are called, have yielded some neat specimens. Some of the earliest known dinosaurs and reptiles roamed this area. Dinosaur tracks of the species of Atreipus and Grallator have been found in the Yocumtown-Goldsboro area. Keep your eyes open during construction of industrial and residential buildings when fresh rock is dug up.
Atreipus foot print found in Adams County
One of the most important fossil sites in southeastern Pennsylvania was found in 1910 near Zions View. This site was excavated by the Pennsylvania Museum and Historic Commission in 1970 and 1971 and yielded bones from a 7-foot long metoposaur known as Butternia and a phytosaur called Rutiodon. Some of these specimens are on display today at the State Museum in Harrisburg; several dinosaur teeth also have been discovered along the Little Conewago Creek and near Roundtown. The site produced very important information about life during the Triassic Period.
Model of Rutiodon at Rocky Hill State Park, CT
Another fossil is petrified wood. With these rocks forming in the Everglades-like environment, wood and plant material was quite common. Several good sites for petrified wood exist between Manchester and York Haven in the vicinity of the Conewago Creek, but one of them has been covered with a housing development. I was told that some large pieces of petrified wood can be found on the banks of the stream near the North George Street bridge, north of Manchester. The railroad cut near Brunner’s Island also contains both petrified and fern fossils, but the railroad company does not allow visitors to the tracks.
Malachite and azuirte at Rossville
As far as minerals go, the most accessible site in the country is found about three-quarters of a mile north of Rossville along Old York Road, where visitors easily can collect a green mineral known as malachite and a blue mineral called azurite. These copper minerals are very colorful! You can’t miss the site on the east side of the road. There is a 6-foot-long hole in the rock where rock collectors have dug out these minerals since 1974. Yes, working in the hole is dangerous, so take a small rake and shovel and look through the many rock pieces lying outside on the talus pile. Although they aren’t large, you can find some beautiful specimens with a little effort. If you enjoy blacklighting, collect some pieces from this exposure and test it for opal hyalite. Opal is found in thin, white-to-colorless seams. Opal shines as a greenish color under a black light.
Location of the iron mines east of Dillsburg
Farther up the road, about one mile east of Dillsburg, you will see Ore Bank Road turning to the north. Along this road in the surrounding woods were about 10 iron mines, many of which include mine shafts. In the many dump piles containing the “junk” rock that wasn’t good enough for iron ore, one can collect an assortment of minerals, including magnetite, orthoclase feldspar, andradite garnet, pyrite, mica and datolite. (By the way, datolite sites in the state are somewhat rare, and this area known as the Dillsburg Magnetite Mine District has yielded some nice samples of this mineral.)
All of these mines and dumps are located on private property. There is some new housing construction taking place in the area, and it’s worth looking at the rock being exposed during this work.
Historic map of the Altland mine
Along Mine Bank Road southwest of Wellsville, rockhounds can find another small cluster of iron mines. The copper mineral malachite can be found here in bladed crystals. In fact, a now-retired geologist with the Pennsylvania Geological Survey told me that some of the best malachite in Pennsylvania came from this area. Again, the few mine dumps are located on private property.
Traveling into central York County, a famous limestone belt parallels U.S. Route 30. As you may be aware, there are a number of active and abandoned quarries in the York Valley. Of course, all quarries are dangerous places. Companies currently quarrying the rock do not allow access because of federal and state regulations and insurance issues. But 40 years ago, when regulations weren’t so tight and companies did allow mineral clubs to collect on weekends while work wasn’t being done, some of the nicest calcite crystals in the state were recovered. Nice calcite crystals are found occasionally at York Building Products’ plant on Roosevelt Avenue. The old Thomasville Stone and Lime Company quarry (now operated by Old Castle and Pennsy Supply) yielded beautiful calcite crystals in the 1950s and 1960s.
Dolomite crystals from Codorus Quarry
Calcite crystal from Codorus quarry
One of my favorite quarries was the Codorus Stone and Supply Company quarry, located northeast of Emigsville. Now under water, this quarry yielded some nice minerals, including fluorite, pyrite, dolomite, hematite, calcite, quartz, barite, sphalerite, barite and chalcopyrite. Most of the specimens were micro in size, which opens another subject for a future entry. Micro-mineral collecting is great fun as you explore a specimen under a microscope wondering just what you will see in the next movement of your hand. I know several micro collectors who have superb specimens.
If anyone is acquainted with the Hellam Hills, keep your eyes open for quartz crystals. Historically, there have been reports of finds in Dee and Dugan runs, including the area around Wildcat Falls. In some cases, the quartz crystals have included reddish-brown needles known as rutile (rutiliated quartz). I have nice quartz crystals discovered near Highmount and close to Wizard Ranch, the Boy Scout reservation. A friend of mine was digging up his old sidewalk on Front Street in Wrightsville and discovered a quartz crystal measuring about 10 inches long and 4 inches in diameter.
Quartz crystal from near Highmount
Stretching from the Cool Creek Golf Club in Wrightsville through Wyndham Hills south of York College westward to Codorus State Park, cubic brownish crystals are common. These crystals were once pyrite (bright yellowish in color and nicknamed “fool’s gold”). Over the years, the pyrite (containing iron) rusted. Rust is known as limonite, but because the crystal remained cubic from the original pyrite, these are today called limonite pseudomorphs. Around new house construction in Wyndham Hills, I have seen crystals about two inches square.
Limonite pseudomorph from York County
Fossils in the form of trilobites have been collected in the limestone and shale areas in the metro-York area. Along Bull Road north of the Rutter’s store across from the former golf course, small trilobites have been collected from a light-greenish shale. A historical site is the shale exposure on the west side of North George Street between Route 30 and Interstate 83. A newer site is found on Locust Lane just west of the overpass of Interstate 83, west of Emigsville. Here, 520-million-year-old trilobites have been collected from the shale.
Do not be disappointed when trying to find a trilobite, as specimens are rare. Remember, during this period of time in the geologic history, life was only starting within the seas and wasn’t abundant.
Because of the metamorphic rocks in the southern third of the county, not many mineral sites are know in the area. But in the fields along state Route 851 in Constitution on the Mason-Dixon Line, one can find rutile, a titanium oxide mineral. These reddish crystals once were collected by local residents and sold to Dentsply in York for use in crafting dental materials. Locals knew rutile as “money stone” because they made a small profit by combing the fields for these crystals.
Again, the fields are on private property and are being used as cultivated fields.
