OAKFIELD — A routine traffic stop resulted in the discovery of about two pounds of marijuana and more than four ounces of crack cocaine, Maine State Police reported Saturday.

A Presque Isle man was arrested on drug charges, and the driver of the vehicle was charged with violating a motor vehicle law.

Robert Van Houten, 32, was charged with trafficking in marijuana and possession of cocaine.

Derrick Gravely, 43, also of Presque Isle, was charged with driving while license revoked.

Both men were transported to the Aroostook County Jail.

Trooper Nick Casavant stopped their vehicle for speeding at about 12:45 a.m. on northbound Interstate 95 in Oakfield, about 23 miles west of Houlton, reported state police Sgt. Brian Harris.

During the traffic stop, Casavant learned that Gravely’s license was under suspension, and further investigation revealed about two pounds of marijuana in the vehicle and more than four ounces of cocaine, according to Harris. The street value of the drugs was not immediately known.

The marijuana was in one container and was not packaged for sale, said Harris. The cocaine also was in one package but was in the form of individual “rocks” or doses of crack.

The investigation is continuing, said Harris.

Casavant was aided by two other troopers, Carman Lilley and Jill Monahan, and also Officer Kevin Reed and a dog from the Presque Isle Police Department.