Carpenter Gothic is a North American architectural style sometimes called Carpenter’s Gothic, and Rural Gothic. The style is an application of Gothic Revival architectural detailing. Aiding the growth of this style was the abundance of North American timber. Carpenter Gothic improvises upon features that were carved in stone in authentic Gothic architecture. The style is seen in small domestic buildings and outbuildings and small churches. It is characterized by a profusion of jig-sawn details. The house carpenters and craftsmen-designers who developed the style were aided by the invention of the steam-powered scroll saw. A common feature is board and batten siding. A less common feature is buttressing, especially on churches and larger houses. Carpenter Gothic details have been applied to brick buildings as well. The style is found in Canada, USA, Australia and New Zealand.
Wikipedia has an article explaining Gothic Architecture as well see http://en.wikipedia.org/wiki/Gothic_architecture
Recommended further reading –
Old Ontario Houses: Traditions in Local Architecture by John Cruikshank, photos by John De Visser R.C.A. http://www.amazon.com/Old-Ontario-Houses-Traditions-Architecture/dp/1552094995/ref=sr_1_1?s=books&ie=UTF8&qid=1346362922&sr=1-1&keywords=Ontario+architecture
Storybook Cottages: America’s Carpenter Gothic Style by Gladys Montgomery http://www.amazon.com/Storybook-Cottages-Americas-Carpenter-Gothic/dp/0847836193