Notebook

It is especially nice to have notebooks which do not fall apart if they get wet.

For reviews of a Rite in the Rain notebook see:

http://www.backpackgeartest.org/reviews/Books/Blank%20Journals/RITR%20-%20Pocket%20Notebook/

Another option for a notebook is to use a biologist/geologist field notebook. These notebooks are hard covered and the first few pages are full of conversions and terms that you might find useful. The pages are lined or graphed. The pages have spaces at the bottom to note the weather conditions and other relevant stuff. They are often available in a waterproof version, but this may not be necessary as they are quite robust and will stand up to a dunking if you dry it out well afterwards. Just use a pencil so the ink doesn't wash away. These books are usually available in any university book shop.

Another good option is to head down to your local surplus store and pick up an FNP - Field Note Pad (I think that's what they call 'em - it's been quite a few years since I bought mine). This is a notepad for which you can get a handy canvas cover with pencil covers and stuff. They really are pretty decent and zip closed so you could keep a compass or a couple of small items in there too. It's not waterproof (though maybe waterproof versions are available) but if it gets a bit wet it will dry well (use pencil pencil pencil).

Whatever type of notebook you choose, take your pencil and roll up some paper around it to form a tube. Then take duct tape the pencil/paper tube combo to the book (I tape mine along the spine). The paper tube should be tight enough that your pencil does not fall out and loose enough that you can pull it out. Voila! instant pencil holder.