Vanessa Fuller, 22, was with her 18-month-old son at the time.

"That is a really big load in a private vehicle," said Roger Maier, spokesman for U.S. Customs and Protection. He said typically agents find from 50 to 150 pounds.

Maier said the street value of the marijuana in New Mexico is between $800 and $1,000 a pound. He said that in Colorado, the street value of the marijuana would be higher - meaning the marijuana recovered Sunday had a street value of about half a million dollars.

Maier said Fuller pulled into the U.S. Customs and Protection border station just before 3:00 p.m. Sunday in Columbus, N.M., after leaving the Mexican town of Palomas.

He said one customs officer initially talked to Fuller and then had her drive to a secondary inspection area. There a drug-sniffing dog picked up on the rear cargo area of the Expedition. 

Click here for Howard Pankratz full story about an Aurora woman stopped with 551 pounds of pot in the Denver Post. 

(Copyright 2010 The Denver Post)