“
... the ... brings to view and differentiates s even in apparently homogeneous rocks. The development of this instrument and of the means of preparing rocks for study marked the beginning of the golden age of descriptive , the last quarter of the nineteenth century. The way had been blazed by , who invented the for , attached it to a , and devised a method for preparing thin sections of (1828). The success of this method led to the epoch-making discovery that and s and some s were composed of skeletons of organisms.
— HERBERT E. GREGORY