Since 1824, when Charles Stokes transmitted to the Geological Society a drawing of the “buccal plates” of Conulus, the question of the existence and characters of the lantern in that genus has been intermittently, but inconclusively, debated. The course of this discussion may be briefly outlined here.

In 1843 Simpson published a description of a Yorkshire Ammonite previously named Ammonites trivialis in Bean's manuscript. A few years later Quenstedt described a number of small continental Ammonites of similar character as A. polymorphus, which he further divided into the varieties lineatus, costatus, interruptus, mixtus, and quadratus. The specimens he then figured must be taken as his types; in a later work he showed many more examples which he referred to the same species; all these have small, evolute shells, but few other common characters, so that the name polymorphus was fully justified. For example, the illustrations given as Ammonites polymorphus mixtus include forms with round or square whorls, with nearly straight or with curved ribs, which may pass across the venter with or without a forward bend, or may be suppressed entirely on the venter. The specimens figured probably include young examples of several different genera.

The name Pahang Volcanic Series was given by Mr. J. B. Scrivenor to those eruptive and intrusive rocks of the Malay Peninsula which are older than the Mesozoic granite, and the rocks were described by him in The Geology and Mining Industries of Ulu Pahang, 1911, ch. xi. As the name implies, the series is most strongly developed in Pahang, but it is also developed to a greater or less extent in Singapore* Island, Johore*, Negri Sembilan*, Selangor*, and Perak*, and possibly also in the more northern states, Kedah*, Kelantan*, and Trengganu*. The present account deals for the most part with the main development in Pahang, and most of the information was obtained on two trips, one to examine the railway-cuttings from Gemas* to Kuala Lipis, and the other to examine outcrops over a distance of about 100 miles in the rivers Jelai and Pahang, from Kuala Lipis to Mengkarak.

The recent paper by A. Holmes on “A Mineralogical Classification of Igneous Rocks” is an attempt to settle a matter which English-speaking petrologists ought to have tackled long ago. There seems, however, to be a disposition, on the part of British geologists especially, to leave the matter alone in the fond belief that some “natural” system of classification will presently be revealed to us whereby all our taxonomic doubts and difficulties will be dispelled. Nothing can be more unreasonable. The philosophic treatment of a subject must follow, not precede, the preparatory work of discriminating, sorting, and docketing; and the sharper the discrimination, the more thorough and orderly the sorting and docketing, the easier to make the philosophic digest. Hitherto petrographers have not discriminated well; we have not done our sorting in a methodical way; we have tied on labels in the most haphazard fashion; our house is in a state of dreadful confusion. It is true that through all the disorder we have caught fascinating glimpses of regularities and relationships; of connexion between this and that; but the deplorable fact appears that we are unable to test or verify any hypothesis, or to take a single confident step towards the philosophic treatment of our subject, until we put our house in order. We have got to do our sorting and docketing all over again, and do it methodically, and then only can we begin to look for the philosophy of the matter.