Classification of Coated Grains: Discussion

In his paper on Classification of coated grains, Peryt (this vol.) subdivides the coated grains in ooids, vadoids, oncoids, and rhodoids. In my opinion, such a classification mixing descriptive (ooids, oncoids) with genetic terms of the same rank (vadoids, rhodoids) is inconvenient. Moreover, Peryt considers the “hot spring ooids” of Richter and Besenecker (this vol.) and some of the ooids discussed by Richter (this vol.) — thermal ooids, cave ooids, aqueduct ooids, and power plant ooids — as vadoids, though this is not justified in my opinion. This was the reason for preparing the following comment.