geognosy

noun

1. (historical, obsolete, uncountable)The geological study of the Earth's structure and composition.

   “Some writers divide Geology into two branches; 1. Geognosy, or Positive Geology, which embraces only the known facts of the science. 2. Geogony, or Speculative Geology, which attempts to point out the causes of those facts, and the inferences that result from them.”