The older interpretation of all sedimentary rocks as marine unless they contain organic evidences of continental origin, and of all continental formations as having formed under estuarine or lacustrine conditions, is no longer adhered to by geologists. Although the greater portion of the sedimentary rocks have originated beneath the sea, yet the origin of any particular formation devoid of fossils must now be regarded as an independent problem. This newer attitude has come about through the recognition of the great value of physiography in the correct interpretation of geologic deposits. From different parts of the world a great mass of data has been accumulated, and viewed in different ways, according as each worker was most impressed with the results of river, ocean, desert, or ice.
Conglomerates may be accumulated and laid down as subaqueous deposits beneath permanent water bodies, as the result of wave action on rocky or gravelly . . .