Simplify the following text for a Grade 11 native English-speaking person.
Original: The Seal of the State of Colorado is an adaptation of the `` Territorial Seal '' which was adopted by the `` First Territorial Assembly '' on November 6 , 1861 .
Simplified: The Great Seal of the State of Colorado is an adaptation of the Territorial Seal which was adopted by the First Territorial Assembly on November 6 , 1861 .