Fossil and Petrology collections, New South Wales The Petrology Collection contains 70,000 rocks and thin sections. It was started in the 1870s as two separate collections, one with 9,000 rocks and the other with 43000 thin sections. Hand written catalogues exist for each. After 1912, only one collection was continued up to the present day. The two old subcollections have much more significance than their sizes would indicate, because much of the material comes from old mine sites, and many of these are no longer available for sampling. Furthermore a few samples, have world significance, such as the thin section from the very sample of Copeton dolerite
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