The answer is ligand gated channels.
Ligand gated channels are also called as ionotropic receptors that open in response to the binding of specific ion, which is generally not solute. These are made up of particular set of transmembrane proteins that open and close to allow the movement of ions like K+, Na+ that passes through the plasma membrane in response to binding of the chemical messenger.
This was a major breakthrough in geology because it meant that sedimentary strata in diverse parts of a country or area could be correlated as belonging to the same formation which means they were formed at the same time historically so helped to put them in the correct sequence. If these strata contained valuable minerals like coal then it could aid in the search for coal. This helped William 'Strata' Smith in England to create his first geological map in the world of a whole country.
Huygens writing about theory of light