Chalk produce, and thus widely used in the developing world, calcium-based chalk can be made where the crumbling particles are larger and thus produce less dust, and is marketed as "dustless chalk". Colored chalks, pastel chalks, and sidewalk chalk (shaped into larger sticks and often colored), used to draw on sidewalks, streets, and driveways, are primarily made of gypsum. Chalk is a source of quicklime by thermal decomposition, or slaked lime following quenching of quicklime with water. In southeast England, deneholes are a notable example of ancient chalk pits. Such bell pits may also mark the sites of ancient flint mines,
Blackboard Inc. to the non-profit IMS Global Learning Consortium developing a prototype for online learning and thinking through online learning standardization. Chasen and Pittinsky started Blackboard after leaving KPMG Consulting where they both had worked as part of the company's higher education practice. In 1998, after Cane met Chasen at a conference on adaptive learning, Gilfus and Cane decided to merge CourseInfo LLC. with Chasen and Pittinky's Blackboard LLC. company in order to raise money and scale the business. The combined company became a corporation known as Blackboard Inc. They renamed the CourseInfo platform built by the Cornell team to Blackboard's CourseInfo;