Astonishing (adj) – causing a feeling of great surprise or wonder
source : merriam-webster
http://www.merriam-webster.com/dictionary/astonishing
Found in “The Cottagette” by Charlotte Perkins Gilman (page 51 paragraph 7)
So I was pleased, though it did interfere with my work a good deal. I always work best in the morning; but of course housework has to be done in the morning too; and it is astonishing how much work there is in the littlest kitchen.
She needs to do her work in the morning but at the same time she has to finish her housework as well. The amount of work in the small kitchen makes her surprise or wonder because there is a lot to do in the kitchen in the morning.