A large part of the credit of showing how fossils are restricted to certain strata, and help to fix the succession and age of the beds, is due to the English geologist and surveyor, William Smith (Fig. 4). "The Father of English Geology," as he has been called, published two works[1] in the early part of last century, in which he expressed his view of the value of fossils to the geologist and surveyor, and showed that there was a regular law of superposition of one bed upon another, and that strata could be identified at distant localities by their included fossils. Upon this foundation the work of later geologists has been firmly established; and students of strata and of fossils work hand in hand. [Footnote 1: "Strata identified by Organised Fossils," 1816-1819; and "Stratigraphical System of Organised Fossils," 1817.] =Stratigraphy.--= That branch of geology which discusses the nature and relations of the various sediments of the earth's crust, and the form in which they were laid down, is called Stratigraphy. From it we learn that in bygone times many of those places that are now occupied by dry land have been, often more than once, covered by the sea; and thus Tennyson's lines are forcibly brought to mind-- "There where the long street roars hath been The stillness of the central sea." =Elevated Sea-beds.--= A striking illustration in proof of this emergence of the land from the sea is the occurrence of marine shells similar to those now found living in the sea, in sea-cliffs sometimes many hundreds of feet above sea-level. When these upraised beds consist of shingle or sand with shore-loving shells, as limpets and mussels, they are spoken of as Raised Beaches. Elevated beaches are often found maintaining the same level along coast-lines for many miles, like those recorded by Darwin at Chili and Peru, or in the south of England (Fig. 5). They also occur intermittently along the Victorian coast, especially around the indents, where they have survived the wear and tear of tides along the coast line (Fig. 6). They are also a common feature, as a capping, on many coral islands which have undergone elevation. [Illustration: =Fig. 5.--A Raised Beach at Black Rock, Brighton, England.= (_Original_). ] [Illustration: =Fig. 6.--Raised Beach (a) and Native Middens (b)= Torquay, Victoria. (Original). ] [Illustration: =Fig. 7.--Marine Fossils (Orthis flabellulum, Sowerby.)= About nat. size. In Volcanic Tuff of Ordovician Age. From the Summit of Snowdon, North Wales, at an elevation of 3571 feet above sea level. (_F.C. Coll._) ] =Sea-beds far from the Present Coast.--=