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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: was set forth in two papers, one entitled " Notes on the Cambrian Rocks of Pennsylvania and Maryland from the Susquehanna to the Potomac,"' and the other " The Geologist at Blue Mountain, Maryland." ' Mr. Keith continued his studies of South Mountain and Blue Ridge geology into Virginia and in 1894 published a report on the " Geology of the Catoctiu Belt." This report describes the Blue Ridge, South Mountain, and Catoctin belts-from northern Virginia through Maryland into Pennsylvania and was an important addition to the geologic knowledge of this area east of the Great Valley. The discovery of fossils in the Frederick Valley limestone was announced by Charles R. Keyes in 1890 in an article in which he included a geologic section across the valley. The next contribution in which fossils were mentioned was by Charles S. Prosser in 1900,' who described the Shenandoah limestone and Martinsburg shale in a general way. The most important contributions to the early Paleozoic stratigraphy of this region appeared in 1910 in the description of the Mercersburg- Chambersburg district of Pennsylvania by George W. Stose" in which E. O. Ulrich collaborated in the study of the Shenandoah limestone and Martinsburg shale. Further stratigraphic and palcontologic details of these rocks were given by E. 0. Ulrich in his " Revision of the Paleozoic System "in 1911.' BIBLIOGRAPHY Jefferson, Thomas. Notes on the State of Virginia. Phila., 1788. Sm. 8vo. 244 pp. The author gives many interesting facts and speculations concerning the geology about Harper's Kerry. Fully ten edltions of this book were published in dlfferent I'liu-es between 1782 and 1832, each with dlfferent number of pages. 1 Amer. Jour. Scl., 3d series, vol. xiiv, pp. 469-482. 2 Nat. Geog. Mag., vol. v, pp. 84-88;...