formation (for mash on)

[=G. Dan. Sw. for mation, The Sixth Day concludes with the Formation of Man. Add is on, Spectator, No. 339. formation 2. Disposition of parts or elements; formal structure or arrangement; conformation; configuration: as, the peculiar formation of the heart; a formation of troops in columns, squares, etc. The doomed men marched on, without any formation. E. Sartorius, In the Soudan, p. 63. The well-disciplined picket had gone right-about-face like a single person. They maintained this formation all the while we were in sight. R. L. Stevens on, Inland Voyage, p. 143, 3. That which is formed; anything considered as to its form, structure, or arrangement: as, the formation consisted of a ma of incongruous materials. Specifically-4. In geol., properly, a group or a emblage of rocks, whether stratified or unstratified, having a similar origin or some common physical character. Some geologists use the word formation as the equivalent of system, or as designating a group of strata having the same geological age. See system. Thus we speak of stratified and unstratified, fresh-water and marine, aqueous and volcanic, ancient and modern, metalliferous and non-metalliferous formations . Sir C. Lyell , Manual of Geology, p. 3. "Formerly it was considered sufficient to collect the more typical specimens of a species, and to be satisfied with a general collection to represent the Formation ." To this is added in a note: "the term formation is in some respects objectionable, but it is convenient, and no satisfactory substitute has as yet been proposed." Prestwich , Geology, p. 5. Alluvial formations. See alluvial. - Free-cell formation. See free. Polar formation, in math., the application of the operation z, D1 + D +, etc. formational (for-ma's hon-al), a. [ Amer. Jour. Sci ., 3d ser., XXXII. 244.