Welcome to the Crowe Bridge Conservation Area ! During summer and early autumn, you should be able to drive within 30-40 metres of the posted co-ordinates. During winter and early spring, the gate will be closed. In the past, you could park outside the gate and walk in, but right now, there is a high fence blocking all access and no way to visit during the off-season months, which is unfortunate. So please wait until June, July and August for your visit. We will keep monitoring this situation to see if winter access becomes available again, as it was before 2020. Once you arrive at the posted co-ordinates, take a minute to look around you, turning yourself 360 degrees (full circle). Observe the geography: the river, the forest, and the pale-grey limestone under your feet and along the riverbank. This Earthcache will cause you to study something else that you might not otherwise notice. There is ancient history in the fossils here, and the fossils here are abundant. In fact, you cannot walk anywhere in this park without stepping on the ancient remains of the sea creatures and plant life that once thrived in this area. The park is easily accessible and stroller friendly.
Questions Please send an email to the CO with your answers at the same time you log your "found it" online. Thanks !
1. At the posted co-ordinates, look down at the rock below your feet. There are fossils here. According to the Turnstone Geological Services (www.turnstone.ca), there are orthoceratite cephalopods and colonial organisms such as bioclasts, bryozoans and coral. But, for the purpose of this Earthcache, you are not asked to identify them. Simply pick one fossil and describe it. By all means, you are invited to try to identify it, but your main task is to DESCRIBE the fossil. Bringing along a magnifying glass is a good idea. Here are some suggestions to use in your description: circular, columnal, convex, concave, spiral, looks like stems, looks like a piece of coral, colour, texture.
2. Include, in your scientific description of your chosen fossil, the size in centimetres or inches. Bringing along a ruler or tape measure is a good idea.
3. Thirdly, tell whether it is a trace fossil or body fossil. Is your fossil raised from the surrounding limestone, flush with the limestone, or indented into the limestone?
4. Finally, look around at other fossils within 2 metres radius of the posted co-ordinates. Are most of the fossils here body fossils or trace fossils?
BONUS : (optional) Sketch a picture of your fossil sample and post with your log.
Description
The Crowe Bridge Conservation Area (CBCA) is a beautiful free public park with parking, picnic tables beside the river, and 25 acres of protected forest. The CBCA is on the south bank of the Crowe River just above its confluence with the larger Trent River, 12 km northeast of the town of Campbellford. The CBCA is composed of predominantly wooded river-bank ecosystems in Seymour township, Northumberland county, southeast Ontario.
Several years ago there was some concern in the local community over the possible sale and development of part or all of this small but well-loved riverside corner of the region. This was resolved with the Municipality of Trent Hills now administering the land for the regional Crowe Valley Conservation Authority. For most visitors, the downstream water attraction at the weir is the key draw in summertime. There are portable potties at the parking lot and picnic tables by the riverside. Enjoy ! 
Geology: A Preserved Record in Fossils
The flat pale grey rock beds you will see here are limestone, classified by geologists in the Ordovician period of the Paleozoic Era. Underneath the limestone there is an older type of rock, mostly granite, which is classified as Grenville Precambrian. Because of annual flooding in the river, there are signs of erosion such as clints and grykes (long skinny ditches) and potholes (circular indentations). Topsoil is unable to establish itself close to the riverbank due to the annual spring flooding and human traffic during the summer, so the limestone is exposed and readily accessible for anyone willing to stop and study the interesting "marks" in the rocks below.
Of interest to geologists and rockhounds like yourselves, are the characteristics of the limestone. This Earthcache invites you to be interested in some features in the limestone by the bank of the river, particularly the fossils.
Typical Fossils in the CBCA
The Turnstone Geological Services (www.turnstone.ca) have identified the fossils in the CBCA as mostly orthoceratite cephalopods and colonial organisms such as bioclasts, bryozoans and coral. The orthoceratite cephalopods were squid-like sea creatures with long shells, growing up to 50-cm-long. They were part of the class which includes squid and octopus, nautiloid and ammonite).
Picture by Nobu Tamura (http://spinops.blogspot.com) - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=19460217
BODY FOSSILS : Body fossils include any part of the actual animal or plant. Things like bones, teeth, shells, and leaves are considered body fossils.
TRACE FOSSILS : Trace fossils are indentations of the creature and give us proof of animal life from the past.
In the above picture of my crinoid stem fossil, the part on the right is the "body" fossil and on the left, you can see its "trace".
Here are some of the CO's sketches of fossils.
Enjoy looking for some of the other predominant features in the limestone:
⦁ Limestone displaying dessication cracks, formed by the baking of a lime-rich, muddy shore under an Ordovician sun.
⦁ Weathering of the limestone forming long cracks (ditches) called clints and grykes, as well as small potholes.
⦁ Darker chunks of rock, about 2-8 centimetres in length, embedded in the limestone, called "chert" which has been used for countless arrowheads by First Nations Peoples over a thousand years ago in this area.
/font>
A big thank you goes out to Skyecat (Barb Murray) for her interest in this Earthcache. She has suggested that one of the corals looks like Saffordophyllum, which is an Ordovician fossil and thus, is consistent with the weblink information.
| I have earned GSA's highest level: |
 |
Link to this webpage for more information : http://www.marmorahistory.ca/crowe-river
and this one : http://www.turnstone.ca/CBCA2010.pdf
Sources :
http://www.turnstone.ca/CBCA.htm Graham Wilson www.turnstone pdf "Natural History of the Crowe Bridge Conservation Area"
www.marmorahistory "The Crowe River, Where it all Began"
Information on this website has been posted with the intent that it be readily available for non-commercial, personal use only. Personal users may download, copy or share the material under the following conditions:
a) The material must not be modified, must retain any associated copyright or other proprietary notices, and must acknowledge the source of the material. b) The source citations should include the URL www.marmorahistory.ca
The Marmora Historical Foundation,
32 Forsyth St., Marmora, Ont. K0K 2M0