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,
What Are Little Girls Made Of? Handlen of "The A.V. Club" gave the episode a 'B+' rating, noting that the "repetitive plotting" took away any real sense of threat and that without Spock or McCoy to play off, Kirk's character is less interesting. What Are Little Girls Made Of? "What Are Little Girls Made Of?" is the seventh episode of the of the American science fiction television series, "". Written by Robert Bloch and directed by James Goldstone, it first aired on October 20, 1966. The first episode of the series to be repeated on NBC, the title of the episode is taken from the fourth