Permission Levels, SPBasePermissions, PermissionMask bit, and default assignments

enum	bit	Group	Enum Name	Name in browser	Description	R	C	D	FC
12	12	List	ManageLists	Manage Lists	Create and delete lists, add or remove columns in a list, and add or remove public views of a list.				FC
10	9	List	CancelCheckout	Override Checkout	Discard or check in a document which is checked out to another user.			D	FC
3	2	List	AddListItems	Add Items	Add items to lists, add documents to document libraries, and add Web discussion comments.		C	D	FC
4	3	List	EditListItems	Edit Items	Edit items in lists, edit documents in document libraries, edit Web discussion comments in documents, and customize Web Part Pages in document libraries.		C	D	FC
5	4	List	DeleteListItems	Delete Items	Delete items from a list, documents from a document library, and Web discussion comments in documents.		C	D	FC
2	1	List	ViewListItems	View Items	View items in lists, documents in document libraries, and view Web discussion comments.	R	C	D	FC
6	5	List	ApproveItems	Approve Items	Approve a minor version of a list item or document.			D	FC
7	6	List	OpenItems	Open Items	View the source of documents with server-side file handlers.	R	C	D	FC
8	7	List	ViewVersions	View Versions	View past versions of a list item or document.	R	C	D	FC
9	8	List	DeleteVersions	Delete Versions	Delete past versions of a list item or document.		C	D	FC
32	40	List	CreateAlerts	Create Alerts	Create e-mail alerts.	R	C	D	FC
13	13	List	ViewFormPages	View Application Pages	View forms, views, and application pages, and enumerate lists.	R	C	D	FC
23	26	Site	ManagePermissions	Manage Permissions	Create and change permission levels on the Web site and assign permissions to users and groups.				FC
19	22	Site	ViewUsageData	View Usage Data	View reports on Web site usage.				FC
21	24	Site	ManageSubwebs	Create Subsite	Create subsites such as team sites, Meeting Workspace sites, and Document Workspace sites.				FC
28	31	Site	ManageWeb	Manage Web Site	Grant the ability to perform all administration tasks for the Web site as well as manage content. Activate, deactivate, or edit properties of Web site scoped Features through the object model or through the user interface (UI). When granted on the root Web site of a site collection, activate, deactivate, or edit properties of site collection scoped Features through the object model. To browse to the Site Collection Features page and activate or deactivate site collection scoped Features through the UI, you must be a site collection administrator.				FC
16	19	Site	AddAndCustomizePages	Add and Customize Pages	Add, change, or delete HTML pages or Web Part Pages, and edit the Web site using a Windows SharePoint Services–compatible editor.			D	FC
17	20	Site	ApplyThemeAndBorder	Apply Theme and Border	Apply a theme or borders to the entire Web site.			D	FC
18	21	Site	ApplyStyleSheets	Apply Style Sheets	Apply a style sheet (.css file) to the Web site.			D	FC
22	25	Site	CreateGroups	Create Groups	Create a group of users that can be used anywhere within the site collection.				FC
24	27	Site	BrowseDirectories	Browse Directories	Enumerate files and folders in a Web site using Microsoft Office SharePoint Designer 2007 and WebDAV interfaces.		C	D	FC
20	23	Site	CreateSSCSite	Use Self-Service Site Creation	Create a Web site using Self-Service Site Creation.
15	18	Site	ViewPages	View Pages	View pages in a Web site.	R	C	D	FC
34	63	Site	EnumeratePermissions	Enumerate Permissions	Enumerate permissions on the Web site, list, folder, document, or list item.				FC
25	28	Site	BrowseUserInfo	Browse User Information	View information about users of the Web site.	R	C	D	FC
31	39	Site	ManageAlerts	Manage Alerts	Manage alerts for all users of the Web site.				FC
30	38	Site	UseRemoteAPIs	Use Remote Interfaes	Use SOAP, WebDAV, or Microsoft Office SharePoint Designer 2007 interfaces to access the Web site.	R	C	D	FC
29	37	Site	UseClientIntegration	Use Client Integration Features	Use features that launch client applications; otherwise, users must work on documents locally and upload changes.	R	C	D	FC
14	17	Site	Open	Open	Allow users to open a Web site, list, or folder to access items inside that container.	R	C	D	FC
33	41	Site	EditMyUserInfo	Edit Personal User Information	Allows a user to change his or her user information, such as adding a picture.		C	D	FC
11	10	Personal	ManagePersonalViews	Manage Personal Views	Create, change, and delete personal views of lists.		C	D	FC
26	29	Personal	AddDelPrivateWebParts	Add/Remove Personal Web Parts	Add or remove personal Web Parts on a Web Part Page.		C	D	FC
27	30	Personal	UpdatePersonalWebParts	Update Personal Web Parts	Update Web Parts to display personalized information.		C	D	FC
1	0		EmptyMask	EmptyMask	Has no permissions on the Web site. Not available through the user interface.
35	1		FullMask	FullMask	Has all permissions on the Web site. Not available through the user interface.

From: http://techtrainingnotes.blogspot.tw/2010/01/sharepoint-permission-levels.html