58 THE JOURNAL OF GEOLOGY. 



ascertained, is permanent. The rocks in question well illustrate 

 the confusing synonomy which arises from the employment of 

 time names. They have been called at various times and by 

 various writers : Silurian, Old Red, Carboniferous, Lower Car- 

 boniferous, Permian, Upper Permian, Mesozoic, Older Mesozoic, 

 Secondary, Middle Secondary, New Red, Trias, Jura-Trias (and 

 synonyms), Keuper, Upper Trias, Rhsetic, Lias, Inferior Oolite, 

 and Oolite. 



When the chronological relations of a stratigraphic unit have 

 been established, it becomes proper to apply to it the title of any 

 time division including its period of formation ; but the need for 

 a local stratigraphic name, or, in other words, an individual 

 name, does not cease. The place of the Hamilton group in the 

 time scale is so well known that it is properly called Devonian 

 and Paleozoic, but the local name Hamilton is still useful. 



In the conceivable case of a formation or group representing 

 the whole of a division of the time scale and no more, there 

 might be a question of the need of a local name. But the exist- 

 ence of such a case has not been demonstrated, and it must be 

 admitted that in the great majority of instances the local strati- 

 graphic units are incommensurate with the standard time units. 

 The body of rocks under consideration is imperfectly supplied 

 with fossils, and little is known of the relations of its fossilifer- 

 ous horizons to one another and to the upper and lower limits of 

 the series. No one asserts that its period of formation was coex- 

 tensive with any of the time divisions whose names have been 

 provisionally applied to it. Opinions as to the interpretation to 

 be given to its fossils are still divergent, and the only name 

 which can be conveniently used by all is one which avoids the 

 question of correlation. A local geographic name meets this 

 requirement. 



There are valid objections to a paleontologic or a purely pet- 

 rographic name, but as such have not been proposed the objec- 

 tions need not be stated. 



3. The proper geographic term is Neivark. — Prominent among 

 the qualifications of a geographic term for employment in strati- 



