Upon discovery of some sandstone deposits in a dried-up river, Mr. Watson questioned Sherlock Holmes on how he could be so sure it's sandstone.
"Why, it's sedimentary, my dear Watson!"
What do you call a lazy sandstone?
A sedentary rock.
What do you call a Graveyard built on sandstone?
Holmes is on the case...
Sherlock Holmes is investigating a murder where the culprit had used a knife carved from Sandstone. Dr. Watson finds the choice of murder weapon odd. "Holmes, who would kill another man with an Igneous rock?" "Sedimentary, my dear Watson, Sedimentary..."