The two seizures were part of intelligence-led operations yesterday evening.
Officers stopped the car on the M74 northbound at Larkhall at around 7.45pm and recovered drugs believed to be amphetamine sulphate with an estimated street value of £1 million.
A 26-year-old man has been arrested in connection with the incident and is expected to appear at Hamilton Sheriff Court on Monday.
In the second incident, officers searched an industrial unit in Balmoral Street, Partick, Glasgow, at around 8.45pm.
They discovered a large-scale cannabis cultivation of 1,100 plants with an estimated street value of £660,000.
Officers are now carrying out investigations to trace those involved.
Police Scotland warned that premises used for cannabis cultivations pose a potentially lethal fire risk and urged landlords to keep an eye out for them and report anything suspicious.
Tell-tale signs include visits to the premises at unusual times, a pungent smell, noise from equipment and windows being permanently covered from the inside.
Detective Chief Inspector Kevin Jamieson, of the Organised Crime and Counter Terrorism Unit (West), said: "We remain dedicated to working pro-actively to rid our communities of drugs, and will take swift action on any information passed to us.
"We are always grateful for any assistance and support from the public, and I would urge anyone with information or concerns about drugs in their local area to contact 101, the non-emergency number for Police Scotland. Alternatively Crimestoppers can be contacted on 0800 555 111, where anonymity can be maintained."