fossil: The Creation of Natural Molds

Sometimes, after specimens were enclosed in the rock formed from the hardened sediments, water percolating through the ground dissolved out the remains, leaving a cavity within which only the form was preserved. This is known as a natural mold. When such molds are discovered by fossil hunters, casts can be made from them by filling them with plastic materials. If molds have been filled with mineral matter by subsurface water, natural casts are formed. Molds of insects that lived many millions of years ago are sometimes found preserved in amber. These were formed by the enveloping and permeation of an insect by sticky pine tree resin which hardened to become amber. So perfectly formed are these molds that detailed microscopic studies can be made of the insect's minute structure. Molds of thin objects such as leaves are usually known as imprints.

Sections in this article:

• Introduction
• The Petrifaction of Remains
• The Preservation of Flesh and Soft Parts
• The Creation of Natural Molds
• The Formation of Fossils
• Bibliography

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2024, Columbia University Press. All rights reserved.

See more Encyclopedia articles on: Biology: General