I differ from Don in a few regards, chisels can be classed by the manner in which handles are attached ie tang and socket. For heavy mallet work in sometimes difficult wood, the heavy body socket chisel is the prefered chisel. Whether the side is beveled, the top relieved or flat top with straight sides, the right chisel is the carpenters choice developed through use. Wide variety existed from late 19th and early 20th century manufacturing concerns. Example 1905 White catalogue
http://toolemera.com/catpdf/lijwhite1905Cat.pdfI would also add to Don's list of chisel types paring chisels and slicks. I have found that a 1 1/2" framing chisel with a long handle and sweep in the blade, so the socket offsets, very handy for many paring tasks.
For the people who work with tall horses firmer chisels make good ergonomic sense until working depth limits are reached.
