This year we have found snails wandering around our compound: Large snails, the type we find in the rice fields.
I hate to kill the creatures (our cook smashes them when she sees them) because their shells are so pretty. But what do you do when there are no calcium containing rocks in your area? Well, here he uses snail shells.
I like the videos because they show how to do everything from scratch.
Survival blog explains why would you need calcium, including quicklime. It is not just used for cement.
as a doc, this is why I might suggest having some around:
Lime can be made from shells, or rocks, but a little known fact is that the settlers of New Amsterdam used the discarded shells found in "middens" ... aka garbage heaps...
after surviving for thousands of years, most middens did not escape the last three centuries unscathed. European colonizers thought of the shell heaps as an obvious available resource for the taking; shells were easily dried and burned into a quick lyme paste, making a sturdy cement for buildings used in the 1600s, and the calcium-rich shells were good for farming and reading soil for crops.
Kurlansky gives a talk about his new book about the history of oysters and oyster eating in NYC:
Kurlansky's books on salt and cod are at Archives, if you sign up as a member. and some of his books are also found at Scribd..again, if you are a member..