Petrology description of rocks while petrography is the speciality that deals with microscopic details. In the petroleum industry, lithology, or more specifically mud logging, is the graphic representation of geological formations being drilled through, and drawn on a log called a mud log. As the cuttings are circulated out of the borehole they are sampled, examined (typically under a 10× microscope) and tested chemically when needed. Petrology utilizes the fields of mineralogy, petrography, optical mineralogy, and chemical analysis to describe the composition and texture of rocks. Petrologists also include the principles of geochemistry and geophysics through the study of geochemical trends
The Philadelphia study development to display any social significance. The nearly completed and most advanced changes displayed the most stability within the study and showed intermediate correlation with the middle classes. The new and vigorous changes—the focal point of the study—displayed the strongest curvilinearity and most clearly encompassed the linguistically innovative nature of the inner classes. Through these Results, Labov asserted the truth and significance of what he named the Curvilinear Principle. With the social information gathered from the interviews, he discovered that it is not the education or occupation factors that drove the middle class to spur linguistic change. Rather, it was