EVELOPMENTS IN GEOLOGY, the sci-ence of the earth, garnered wide publicity in the popular press of the nineteenth century and affected the way artists depicted the landscape. An examinationof specific paintings in the context of the heatedly discussed scientific issues of the day leads to a better understanding of the meanings that the artists were seeking to convey. Those artists who became increasingly conversant with geological concepts and their visual representation in scientific reports self-consciously changed the way they looked at and painted the earth in the 1870s. Armed with scientific data gleaned from books and articles, they moved from painting pastoral landscapes that expressed aesthetic ideas toward geological renderings that specifically focused on scientific ideas. Among scientists and laymen the most important concept discussed at midcentury was geological time. It raised significant questions about the validity of traditional theories about the origin of the earth and sparked debates that fascinated a generation or more of lay readers who sought to reconcile the divergent theories and new data. American landscape painters began incorporating scientific aspects of rocks and geological formations in their paintings as early as the 1820os. It was at midcentury, however, that they were most encouraged to include scientific information in their works. This encouragement was given explicitly in books and articles such as Alexander von Humboldt's Cosmos, John Ruskin's Modern Painters, and Louis Agassiz's essays on geological research and by the data emerging from the surveys of regionsin the West that had previously been largely unexplored. All of these combined to make artists more aware of the science of the earth and of ways in which it could be incorporated in an artist's painting vocabulary.'

An important geologic issue that captured artists' attention was geological time. In 1830 geologist Charles Lyell, an Englishman, set forth the theory of uniformitarianism (the hypothesis that the earth was formed slowly and uniformly over eons of time). Lyell's theory challenged the scientific accuracy of the biblical account of creation and argued against French geologist Georges Cuvier's theory of catastrophism (the hypothesis that the earth was formed quickly by a series of catastrophes punctuated by periods of calm). The religious implications of Lyell's theory made the issue of geological time vis-a-vis the age of the earth both significant and controversial. Ever since geology had been recognized as a science in 18oo, people had raised questions about the age of the earth, and Lyell's hypothesis intensified the discussions. By the 1850s the debates between the catastrophists and the uniformitarians yielded to discussions of how to comprehend geological time. The shift reflected the growing scientific and public acceptance of Lyell's theory and its very important corollary: that geological time was infinite. In 1856 a reporter pronounced to his literate public," the antiquity of the Earth" is" so vast as to be illimitable." Yet the concept was daunting. Agassiz categorized" the immense periods which have