What type of rock would you form in this environment, showing a dried up lake bed?

In a dried up lake bed, it is expected for rock salt and evaporite minerals to be observed.

Rock salt, or halite, is the mineral form of sodium chloride ("NaCl" or table salt). Evaporite is a general term for water-soluble mineral sediments that form from the concentration and crystallization of the "mineral-containing (aqueous) solution," mostly by evaporation. They are considered as sedimentary rocks.

Lakes are freshwater bodies and thus usually form non-marine evaporites while oceans and seas form marine evaporites. Nonmarine evaporites include  blödite, borax, epsomite, gaylussite, glauberite, mirabilite, thenardit, trona, and also halite, gypsum, and anhydrite (which are more commonly found in oceans and seas). 

The answer your looking for is a food chain grid. it describes how nature can support itself and survival of the fittest comes into play..