182 Scientific Intelligence. 



(vol. xx, pp. 445, 446). So far as the writer is aware, Buena 

 Vista as the name of a geological division was first used by Dr. 

 Edward Orton in his report of Pike county, Ohio, and published in 

 1874. The terai'was applied to a subdivision of the Subcarboni- 

 ferous (Mississippian) rocks of southern Ohio, and Dr. Orton's 

 statement was as follows : " This subdivision has a definite base, 

 viz., the upper surface of the Waverly black slate [now known as 

 • the Snnbury shale] ; but there is no characteristic stratum that 

 constitutes a convenient superior limit. As the most valuable of 

 the building rock, however, that is furnished by this part of the 

 series in southern Ohio occurs within fifty feet of the slate, these 

 fifty feet next above the slate may be somewhat arbitrarily taken 

 as a subdivision. It may be designated as the Buena Vista sec- 

 tion — the name being derived from a locality on the Ohio River 

 that furnishes a large amount of stone of unequaled quality." 

 (Rept. Geol. Surv. Ohio, vol. ii, Pt. I, p. 626.) This name was 

 revived, the upper limit of the terrain defined, and applied to the 

 lower member of the Cuyahoga formation in southern and cen- 

 tral Ohio by the writer in December, 1904 (Amer. Geol., vol. 

 xxxiv, f.n. on pp. 341, 342). In view of the above facts it does 

 not appear to the writer that Buena Vista is available for the 

 name of a Cambrian formation of Virginia. 



13. The Configuration of the Rock Floor of Greater New 

 York ; by "William Herbert Hobbs. 1905. Bull. No. 270, 



U. S. G. S. Pp. 96, Plates V, figs. 6. — The present is an espe- 

 cially favorable time to study in detail the structure of the rock 

 floor of Greater New York by means of the bore holes and exca- 

 vations which have been made in the course of engineering opera- 

 tions. This information if not now collected would be ultimately 

 largely lost and Professor Hobbs, perceiving this some years ago, 

 has collected a large amount of geological information which 

 will be of the highest importance to engineers engaged in con- 

 struction work. The details also have bearings, as Professor 

 Hobbs points out, upon structural problems in the geology of the 

 region. j. b. 



14. Formation of Phenocrysts in Igneous Rocks. — In his open- 

 ing address before the Geological Section of the British Associa- 

 tion for the Advancement of Science at the meeting in South Africa, 

 Prof. H. A. Miers, president of the section, alluded to a number 

 of important problems in geology whose elucidation is greatly 

 aided by experimental research. Chief among these is the difficult 

 question of the differentiation of igneous magmas and the origin 

 of igneous rocks. After mentioning the results attained by dif- 

 ferent workers in this field the speaker gave some of his own 

 results obtained in the study of the cooling and crystallization of 

 saturated solutions which tend to throw light on rock textures. 



Ostwald had previously shown that a saturated solution can exist 

 in such a condition that crystallization may take place sponta- 

 neously or be readily induced by shakingyetc; this is termed the 

 labile state. On the other hand, the solution may be in such a 



