Leelanau Peninsula Field Trip
Leelanau State Park, Michigan
March 11, 2006
Jim Adams

Hi everyone,

With Spring just beginning to win it's battle over Winter, Saturday March 11th was a day to get out and see places we'd never seen.

For now, my mineral collection is concentrating on local minerals, and the obvious choice for a new rockhound like myself is to search for is our state stone, the Petoskey. The geology of this fossil coral has been explained to perfection already by the host of this website. Suffice it to say that these stones are remnants of an ancient coral reef that stretched across northern Michigan in an arc from Sleeping Bear Dunes to Alpena around 350 million years ago. The latin name is Hexagonaria percarinata.

Research on the Petoskey Stone lead me to Mike Streeter's report on "Collecting in a Gravel Pit, Northern Michigan".

Click Here For Report

Here I learned about the Traverse formation being the location of Petoskeys. Comparing my map of the bedrock geology of Michigan with my Michigan Atlas, I found the Leelanau State Park, where right on the map in Cathead Bay it says "Petoskey Stones". I checked the DNR website for Leelanau State Park, were in two places on the page it says, "Petoskey stones can be found here." So I emailed the Michigan DNR to see if it was alright to rockhound at the beach. They didn't seem to want to discourage rockhounds from visiting the beach, but said to take only one stone, so that others could enjoy the beach as well. So I only took one stone, but it was a nice one.

Our day started early at 4:30am. I figured it would be about a 4 hour drive, and wanted to have lots of time for hunting. We left the house shortly before sunrise, around 6:00.

The snow had been melted around our house for about a week, and on our drive up, we started seeing more snow around Mt. Pleasant.
M115 to Cadillac is a beautiful drive. We saw a large Bald Eagle flying off with a fresh catch, and several deer.

We arrived in Traverse City sooner than expected. I had planned on visiting a local rock shop that I found on the internet, but since we arrived at Davidson's Rock Shop about an hour early, I decided to head out to the beach and try to stop back later in the day.

It was a picture perfect day (for early March) when we arrived at Leelanau State Park. The immaculate lighthouse was a wonderful sight.

On the drive up, my wife Litha was slightly concerned about the amount of snow we were seeing, but I assured her it would be ok. I had been watching a website that showed snow cover in the area for a few weeks, and now it showed less than an inch (sure, in places). I had talked to someone on the phone in Rapid City, Michigan who said they still had two feet of snow in places. I had so much faith in the snow cover map, that I told Litha, if there was two feet of snow on the beach I would bare my hiney and sit in that snow! Well, it's a good thing she didn't "hold" me to that statement. Near the water's edge, the ice and snow pack was two feet thick and more in some places. I um, told her the ice and snow pack doesn't count.

Dispite the snow, there were still plenty of rocks exposed. Unfortunatly most were covered with last year's algae, an it was hard to tell one from another. As far as Petoskey Stones go, Cathead Bay was a bust, but I did find one specimen I thought was pretty darn cool. It's a large intact fossil coral colony.

It measures 13.5" long by 11" wide and 6"thick, and weighs 48.6 pounds. I probably carried this rock a quarter mile back to the van through rocks and snow.

Our next stop down the beach was Peterson Park.

My atlas showed a swimming beach here, but when we got there it was a fairly sheer cliff with no easy way down, and if we did get down safely, how would we get back up carrying rocks? It looks like a back pack will be next on my list of rockhounding tools. This park had a beautiful view, but we moved on south to more promising locales.

Our next stop was the municipal beach in Leland. Here there was much less snow than at our previous stops. There is a small public parking area with access to the beach.

I decided to wear my hip boots this time, and I'm sooo glad I did. This beach turned out to be so productive that we spent more time there than we intended.

I also learned what hypothermia must feel like, continually dipping my right arm in the ice water.

We started finding these "stones" that had the nicest shades of blue from turquoise to almost a lapis blue. After talking with some very nice local ladies (themselves rockhounds) we learned they were called "Leland Bluestone", and thanks to Mike Streeter's prowess with the Google search engine, we learned that this is actually a man made byproduct of the iron foundry that built the Leland Dam. Not a true stone, but very pretty and could be made into some nice jewelry. I think it's also an interesting part of local history.

I also found some nice pieces of red jasper and what I think is Unakite.

But the order of the day was Petoskey Stones, and I'm happy to say we weren't disappointed. We didn't find large pieces I was hoping for, but what was lacking in size was made up for in quantity. We even found some small Petoskey Cousins that are made mostly of white Calcite.

This natural Petoskey cabochon (below) has a fairly distinct image on it to my eye, but I don't want to influence the reader's impression, so I won't say what I think it is quite yet. I asked Litha what she thought it was, and she came up with something completely different, so let's see what you think.

And finally all my Petoskey Stone finds.

We left Leland around 3:00 and took the lovely drive across Lake Leelanau and through Orchard country. If I had known then what I know now, we would have stopped for some cherry wine tasteing. I wanted to get back to Traverse City before Davidson's Rock Shop closed, but we were too late. The Saturday hours closed at 2:00.

Oh, well, I had to work the next day, and we had a long drive ahead, so we set our sights for home, arriving shortly after sunset, providing a nice sort of symmetry to the the day's beginning.

It was a wonderful roadtrip to a unique part of the state we'd never have gone to if it weren't for my newfound obsession. My thanks go to Mike Streeter for his help with identification, and having this website to begin with.


Jim Adams