The characteristics of the distribution of bi-, tri-, tetra-, and pentacyclic terpanes in Jurassic and Cretaceous Kalmykia crudes were investigated. It was found that these crudes are distinguished by high relative concentrations of tri-, tetra-, and pentacyclic C-19-C-35 terpanes and C-14-C-16 bicyclic terpanes (sesquiterpanes). It was shown that these crudes contain all ten of the C-14-C-16 sesquiterpanes usually present in crude oils and that the Jurassian and Cretaceous crudes can not only differ with respect to the generally accepted indexes - tri-, tetra-, and pentacyclic terpanes, but also with respect to these hydrocarbons.