Which Had Bigger Impact On Westward Expansion 1800-50 or 1850-90

Question 1

what has bigger impact

Answer 1

1800-50 set foundations for the ability to move west. examples being Lewis and Clarke expedition where they made maps and trials throughout Louisiana, fur trappers. whereas after 1850 was where mass migration happened and gold rush, land grants which was all possible because of the pioneers in 1800-50