It is NOT a crack. It is a manufacturing flaw which was quite common at the time. The label shows some edge wear, but the glass is clear and free of cracks or chips. It was made to commemorate the opening of the St. Lawrence Seaway. The lid features a picture of Queen Elisabeth and Prince Phillip.
Piece shows some wear, but is in overall good condition.
Minnesota - This vintage tray is beige with 3 flying geese. Minn. Probably in the 60's. Shows some edge wear but is otherwise in good condition. Underside has some rust. Silhouette Thermometer - This vintage Silhouette Thermometer measures 4x5.