Medium-grained rocks can be composed of quartz grains, feldspar grains (arkose), or rock fragments and clay (graywacke). Sandstone (Photograph by Parvinder Sethi). Medium-sized grains in clastic sedimentary rocks form sandstone. This sample is a quartz sandstone.
Bliss â¢ McCabe: Discourse Genres 135 special interests and can give lengthy descriptions ofrelevant objects such as rocks or music).â¢ We have identified the following components thatappear to be necessary for a complete proceduraldiscourse regarding how a game is played: goals,players, materials, and procedures.
Rhetorical modes (also known as modes of discourse) describe the variety, conventions, and purposes of the major kinds of language-based communication, particularly writing and speaking. Four of the most common rhetorical modes and their purpose are narration, description, exposition, and argumentation.xpository writing is a type of writing where the purpose is to explain, inform, or even describe. It is considered to be one of the four most common rhetorical modes. The purpose of expository writing is to explain and analyze information by presenting an idea, relevant evidence, and appropriate discussion.