Nature Study
First, what did Charlotte Mason say about Nature Study? For compilations of nature study/science quotes, see the following two resources.
For further information and ideas :
Books/"Curricula" for Nature Study
Note : Also see John Muir Laws website for a wealth of information on nature journaling and nature drawing, and also a (FREE!) pdf guide on How to Teach Nature Journaling.
Equipment Lists
Nature Journals
Tip : You can find a nice nature journal at art/craft supply stores like Michaels, Hobby Lobby, or JoAnn. Some features that you may like to look for : Spiral bound (so that it lays flat), Watercolor paper pages (if you're planning to use watercolors), hard cover (for protection), and small enough to hold in one hand while sketching with the other.
The following are some options available online recommended by other CM homeschoolers :
Books for Encouragement
The following are some books for homeschooling parents to read to help encourage you to get outside in nature with your kids.