Febetjabt 23, 1906.] 



SCIENCE. 



287 



Secondly, a teclmical term should be ety- 

 mologieally appropriate. 



The words synclinorium and anticli- 

 norium were introduced by James D. 

 Dana.^ According to the form of the eon- 

 traction theory of mountain-making devel- 

 oped by Dana, most monogenetie mountain 

 ranges were believed to have been made by 

 the crushing of the strata in a geosyncline. 

 Such a range he proposed to call a syn- 

 clinorium. The final part of the word is 

 from opo's, mountain, and the word is alto- 

 gether appropriate etymologically. Dana, 

 however, recognized that a somewhat per- 

 manent line of elevation might be formed 

 as a geanticline, a considerable area of the 

 crust being elevated into a gentle arch with- 

 out any considerable disturbance of the 

 strata. Such a range he proposed to call 

 an anticlinorium. As an example of an 

 antielinorium he cited the 'Cincinnati Up- 

 lift' formed in mid-Paleozoic time, nearly 

 contemporaneously with the Taconic syn- 

 clinorium. 



The words synclinorium and anticli- 

 norium are accordingly not stratigraphic, 

 but orographic terms. They denote two 

 types of mountain elevations. 



I believe the antielinorium type is more 

 important than Dana himself supposed. 

 The Appalachian range, for instance, was 

 formed as a synclinorium in post-Carbon- 

 iferous time, subsequently peneplained, 

 and reelevated as an anticlinorium in Ter- 

 tiary time. This remark is made in pass- 

 ing, as it is not my purpose at present to 

 discuss the theory of mountain-making. 



It is much to be regretted that several 

 recent writers have used the words in en- 

 tirely different senses. Van Hise unhap- 

 pily set the example in his masterly — his 

 really epoch-making— studies of rock de- 

 formation.^ He uses the words in a purely 



- American Journal of Science, Series 3, Vol. 5, 

 pp. 431, 432. 



'Journal of Geology, Vol. 4, p. 319. 



stratigraphic sense, making an anticlino- 

 rium simply a compound anticline, and a 

 synclinorium a compound syncline. He 

 distinguishes synclinorium and antielino- 

 rium from geosyncline and geanticline, 

 using the latter pair of words substantially 

 in the sense in which Dana used them. 

 The etymology of the words synclinorium 

 and anticlinorium is as inappropriate in 

 the new sense as it was appropriate in the 

 original sense. 



Sir Archibald Geikie* and Scott^ follow 

 in the footsteps of Van Hise, distinguishing 

 synclinorium and anticlinorium from geo- 

 syncline and geanticline, but using the 

 former pair of words in the sense simply 

 of compound folds. Geikie explicitly at- 

 tributes to Dana the usage which he fol- 

 lows, but has apparently taken his defini- 

 tions from Van Hise without referring to 

 Dana's paper. 



Chamberlin and Salisbury' have intro- 

 duced a further confusion by treating syn- 

 clinorium and anticlinorium as synonyms 

 respectively of geosyncline and anticline. 



It is, perhaps, too late to restore the 

 words to their original sense, after they 

 have been used in other senses by writers 

 of so high authority. Yet such restoration 

 seems very desirable. 



The Overlap of the St. Stephens Limestone 

 on the Lower Tertiary Formations in 

 Crenshaw and Pike Counties, Ala.: 

 Eugene A. Smith. 



The paper described, with the aid of a 

 map, a case of overlap of the Vicksburg 

 limestone on the Nanafalia division of the 

 lower Tertiary, where the former occurs 

 in detached patches in the territory of the 

 latter. The whole series of the intervening 

 Tertiary formations outcrops between these 



* ' Text-book of Geology,' latest edition, pp. 678, 

 679. 

 ° ' Introduction to Geology,' pp. 236-238. 

 "'Geology,' Vol. 1, pp. 480, 481. 



