The work is primarily a geography and is arranged by countries and places, beginning with Rome and Italy. As each locality is considered, Solinus sometimes tells a little of its history, but is especially inclined to recount miraculous religious events or natural marvels associated with that particular region. Thus in describing two lakes he rather apologizes for mentioning the first at all because it can scarcely be called miraculous, but assures us that the second “is regarded as very extraordinary.”[1475] Sometimes he digresses to other topics such as calendar reform.[1476] Solinus draws both his geographical data and further details very largely from Pliny’s _Natural History_; but inasmuch as Pliny treated of these matters in separate books, Solinus has to re-organize the material. He also selects simply a few particulars from Pliny’s wealth of detail on any given subject, and furthermore considerably alters Pliny’s wording, sometimes condensing the thought, sometimes amplifying the phraseology—apparently in an effort to make the point clearer and easier reading. Of Pliny’s thirty-seven books only those from the third to the thirteenth inclusive and the last book are used to any extent by Solinus. That is to say, he either was acquainted with only, or confined himself to, those books dealing with geography, man and other animals, and gems, omitting almost entirely, except for the twelfth and thirteenth books, Pliny’s elaborate treatment of vegetation and of medicinal simples[1477] and discussion of metals and the fine arts. Solinus does not acknowledge his great debt to Pliny in particular, although he keeps alluding to the fulness with which everything has already been discussed by past authors, and although he cites other writers who are almost unknown to us. Of his known sources Pomponius Mela is the chief after Pliny but is used much less. On the other hand, the number of passages for which Mommsen was unable to give any source is not inconsiderable. As may have been already inferred, the work of Solinus is brief; the text alone would scarcely fill one hundred pages.[1478] [Sidenote: Animals and gems.]