"The Cliffs"

The geological history of Brownie's Beach

Brownie's Beach lies at the northern most tip of the famous Calvert Cliffs. 
If you wade out in to the bay, and look back at the cliffs from a distance, you can clearly see several distinct layers. It may be hard to see, but most of these layers slowly dip down as you go further south. So as you go south, the deposits at a certain level get younger. Except for the very top, which contains more recent material, this trend is true along the entire length of the Calvert Cliffs. So Brownie's Beach at the northern most tip is also the oldest part of Calvert Cliffs. The oysterbed, Shattucks zone 4, is an exception to this trend. 
The deposits at B.B. are part of the Calvert Formation which, as the time table below shows, was formed in the early-middle age of the Miocene epoch of the Tertiary period of the Cenozoic era of the Phanerozoic eon. Pffft. The total thickness of the Calvert formation is about 60 meters, but part of that is already below ground/water level at B.B. 
A kilometer south of Governor's Run, the Calvert Formation disappears completely below beach level. On top of the Calvert Formation lies the 15-30 meters thick Choptank formation, which in turn disappears below ground level near Calvert Cliffs State Park. And on top of the Choptank formation lies the St. Mary's formation. This trend is very clear in the geologic map of Calvert County at the Maryland Geological Survey
Within each formation, you can identify distinct layers, from fine blue clays, to coarse red sands. These are called Members. Different members were deposited under different circumstances, from shallow seas to tidal flats, and contain different types of fossils. 

EON

ERA

PERIOD

EPOCH

AGE

FORMATION
(in Maryland)

TIME

P
h
a
n
e
r
o
z
o
i
c

Cenozoic

Quaternary

Holocene

 

 

0-10000yr

Pleistocene

 

 

10000yr-1.6Myr

Tertiary*

Pliocene

 

 

1.65-5.2Myr

Miocene

late

Eastover

5.2-25.2Myr

St. Mary's

middle

Choptank

Calvert

early

 

Old Church

Oligocene

 

 

25.2-36Myr

Eocene

 

 

36-54Myr

Paleocene

 

 

54-66.5Myr

Mesozoic

Cretaceous

 

 

 

66.5-144Myr

Jurassic

 

 

 

144-213Myr

Triassic

 

 

 

213-248Myr

Paleozoic

Permian

 

 

 

248-286Myr

Carboniferous

Pennsylvanian

 

 

286-360Myr

Mississippian

 

 

Devonian

 

 

 

360-408Myr

Silurian

 

 

 

408-438Myr

Ordovician

 

 

 

438-505Myr

Cambrian

 

 

 

505-544Myr

P
r
o
t
e
r
o
z
o
i
c

Late

 

 

 

 

544-1000Myr

Middle

 

 

 

 

1000-1600Myr

Early

 

 

 

 

1600-2500Myr

A
r
c
h
e
a
n

Late

 

 

 

 

2500-2900Myr

Middle

 

 

 

 

2900-3400Myr

Early

 

 

 

 

3400-3900Myr

*)Sometimes the Tertiary is split into the Neogene (Pliocene, Miocene) and Paleogene (Oligocene, Eocene, Paleocene) periods 
Much more recently, streams and rivers have cut down through the many layers and created gaps in the cliffs. These gaps form the present-day beaches, such as B.B. Because of the impermeable clays, several of these gaps are filled with swamps thriving with turtles, water snakes and even a beaver lodge. A walk through Calvert Cliffs State Park is definitely worth it!

Turtle

turtle
Beaver lodge

beaver lodge
Black snake

black snakes

Where is Brownie's Beach?

Brownie's Beach is one of the few publicly accessible beaches on the western shore of the Chesapeake Bay. Locals continue to call in Brownies Beach or Randle Cliffs but it is now formally known and designated as BayFront Park - the only public park along the Calvert Cliffs that does not charge an admission fee. It lies just south of the village of Chesapeake Beach and is impossible to find if you don't know where to look. So here are the directions (from the North): 
1. Get yourself on route 2, which runs south from Annapolis. If you are coming from Baltimore, take the I-97, and immediately exit when it merges with routes 50/301 east, and follow the signs for Solomons Island Rd. 
2. Stick to the speed limit, there are plenty of patrol cars... 
3. Stay on route 2, past the round-about which you have to take for 3 quarters. 
4. Take the exit to Chesapeake Beach, at the (2nd) traffic lights. This gets you on route 260. 
5. Follow 260 until it ends at a traffic light in Chesapeake Beach, and take a right on to 261. You should have seen the waters of the Bay straight ahead as you drove in. (When you have time, go left here, and enjoy the beautiful board walk and beach in downtown North Beach!) 
6. Drive all the way through Chesapeake Beach. If you have kids, you could visit the water park on your right first. After your visit to the beach you will be too smelly ... 
7. Just outside of town you drive down a little hill. At the bottom of the hill is a shoulder on the left hand side of the road, and a dirt-road disappears into the forrest, leading to a little parking lot (sounds just like one of the early text-based adventure games). If it is really busy you may have to park on the shoulder. 
8. From the parking lot it is about 200 meters (650 feet for the non metric folks) to the beach. 
9. Except when vandalized, there are two "porta-potties" near the beach. 

What to bring?
Here is an annotated version of the list we have hanging on our kitchen bulletin board: 

  • Water & Food! 
    Especially in the summertime you should bring enough to drink. In the winter you may want to bring something warm: tea, cocao, coffee. 

  • Sun-screen
    Especially in the summer. We always wear T-shirts, though we learned that a white T-shirt provides no sun-block at all... ouch! In the mornings there is no shade at all. In the afternoon the cliffs provide some shelter. 
    screens 

  • The tools of the trade. Roughly one square foot piece of 1/4" screen in a wooden frame. The screen can be bought by the roll at any Home-Depot/Lowe's. If the frame is flat, you can use it for scooping. If you have a box screen, you also have to bring a shovel. 

  • Shoes 
    Because of too many broken bottles, and other sharp objects (crabs!) you want to wear shoes when you are walking through the water. Wash them when you get back home, and don't expect to wear them to any party soon. 

  • Hip-pouch 
    Or something else you can put your finds in. Remember that you want to have both your hands free to search. 

  • zip-locks 
    In case your pouch fills up. 

  • Wash cloth, soap, more water 
    Your hands will be really smelly from the Bay, and you want to bring something to wash them with afterwards. 

  • Towels 
    Obvious 

  • Waders 
    When the water gets colder, or there are too many jelly-fish, you may want to own a pair of waders. You can go for the more expensive rubber ones with connected boots, but these are bulky, and it is hard to bend over, which is what you will be doing most of the time. We opted for the cheap nylon waders ($8.- K-Mart, Wal-Mart), which end in socks instead of boots, and we wear our shoes over them. 

  • Dry clothes 
    just in case. 

How to search?

Here are a few tips on how to improve your chances of finding shark teeth and other fossils.

never, ever dig in to the cliffs! 


We have seen parts of it collapse, and you do not want to be near them when that happens. Depending on their height you want to be at least 20 feet away. Also, all the land above your head is privately owned, and if you dig away at a cliff someone's forrest or garden is going to shrink. If you dig in the beach, fill in any holes you make, or somebody might sprain an ankle or worse. 
Don't get in the way of other collectors or sunbathers. There are no magical spots. Of course you are free to show your great finds to anybody on the beach, or to inform after their finds of the day. 
Be patient. The very first time, you still have to train your eyes to pick out any fossils from the thousands of pieces of shell. But after a few finds, you will learn to recognize them pretty easily. 
If the waves dump fresh material on the beach, or wash away sand, you can pick up teeth straight from the beach. On Brownie's Beach it doesn't really matter where you search. The entire beach is covered with fossils. In a single summer afternoon the two of us routinely find 300-400 teeth, 50 fragments of ray dental plates, 6 porpoise teeth and a pint of bone fragments. And the next day we can do it all over again. 
Except when the tide is very low, most of the fossils will be a few feet into the water, jumbled with all the shells and shell fragments. Shark teeth resemble little shells, so where you find shells, you will find shark teeth! The surf is like a giant sorting machine. If you walk further in to the Bay, you will notice that the bottom is completely clean. No shells and no teeth. The surf has dumped everything nicely near the beach. 
Scoop up a pile of shells on your screen, and wash out all the sand and small fragments by gently shaking the screen under water. Stand up straight to relax your back, and see what you got. 
Sometimes the surf has replaced the shells with little pebbles. The shape and density of pebbles resemble those of broken pieces of larger teeth, bones and larger porpoise teeth, and you will find more of those between the pebbles. We once found more than 6 one-inch porpoise teeth in a few minutes in such a pebble bank. 
Many larger dark objects are either broken beer bottles or pieces of fossilized bone. If you can tell it is bone but you don't know whether it is a fossil or a fresh bone, try to hit it with a piece of stone, or tap it against your teeth (without swallowing anything...). If it feels like rock it is a fossil. There are many fresh bones of recently drowned deer or larger fish. If you accidentally bring one of these home, the smell will make it very clear you made a mistake. Fresh bones are whitish, fossils are brown or black, and stay brown or black when you clean them. 

When to search?
If you want to search on the beach, you probably want to get there when the tide is receding. If you are willing to get wet, it doesn't really matter too much when you show up. The average difference between high and low tide is only about 30 cm (1 foot). 
We use David Flater's great xtide program. It can compute the tides for many shores world-wide, including those for Chesapeake Beach. 
And when you think 8am is early, you'll be surprised to see people walking off the beach, still carrying their flashlights - when they arrived it was still dark.... 

When you get home
When you get home, you want to wash your finds in fresh water, to clean them from any sand, clay or smelly stuff. If you found any bones, you should leave them in a bucket with regular tap water overnight. This will wash out some of the salt from inside the bones. If you dry them too quickly, the salt will grow little crystals when the bones dry, and will cause cracks or complete fractures. 
Don't dry your finds too fast, and keep them from direct sunlight. 
If you found a large bone, such as a dolphin vertebra, and notice that it is slowly crumbling, here's one cheap way to consolidate it. Get yourself a family size bottle of "Elmer's Glue-all". Mix the Elmers 50/50 with water in a container that will hold your fossils, and submerge each bone for several hours, so that the glue can seep into the cracks. Carefully take the fossils out; the soaking may have made them even more fragile. Wipe off any excess glue to prevent shiny surfaces or white crud, and let it dry. 
Now you can sit down and sort through your finds. 
If you collect from more than one location, make sure to keep your finds in separate containers, boxes, drawer, baggies, and keep track what you found where.

* This information was compiled by CMMFC member Edwin Huizinga. Thanks Edwin!!!