Abstract
It is standard practice for geologists to compare the sedimentary structures found in rocks with the sedimentary structures found in modern day deposits. Many contemporary environments of deposition are recognized, such as fluviatile, eolian, lagoonal, deltaic, neritic and pelagic. The uniformitarian geologist seeks to classify sedimentary rocks in the same way, for he believes that these modern analogues are sufficient to interpret the past. The geologic literature is replete with uniformitarian terminology, so that, for example, particular rock formations are described as having been found in deltaic or in fluviatile environments.