On the Geological Signification of the word “ Flysch.” 147 
by restricting it to the slaty arenaceous fucoidal formation, which 
covers the nummulitic formation among the Alps and Apennines. 
For my own part, I felt the need of a petrographic name to desig- 
nate the whole of the slaty and arenaceous rocks which, among the 
Alps, entered between the different limestone chains and the masses 
of gneiss and protogine, and whose geological position remains un- 
certain ; because the fossils found there are insufficient to determine 
their age,—as in Maurienne, Tarentasia, in the Valais, in the Gri- 
sons, and other parts of the Alps. Finding the formation superior 
to the nummulites described under the name of Macigno and Albé- 
rése, by M. Pareto and other Italian geologists, I proposed to adopt 
this name with the epithet ‘“ Alpine;” and I named “ Alpine 
Macigno” what M. Escher called Flysch, while I thought we should 
reserve the latter name to designate systems of rocks very similar to 
the true macigno, but whose age and geological position remain un- 
determined. 
I adopted this latter nomenclature in all that I have written since 
1840, while, in the Memoir on the Alps of Lucerne, inserted in the 
Memoirs of the Geological Society of 1838, I conformed to the no- 
menclature adopted by M. Escher. According to my manner of 
speaking, there may be flysches of all ages; the name will be al- 
lowed to drop, in relation to each group whose geological position is 
definitively fixed by agreement of fossils and position ; and, if it be 
possible for us to attain this object, in regard to all the Alpine 
groups, the name Fysch will be at last discarded from our geological 
terminology. 
Explanation of the Treatment of an Invention in Lithography 
made by Mr Schenck and Mr Ghemar of Edinburgh, in August 
1849. (With a Lithographic Plate.) Communicated by 
the Royal Scottish Society of Arts.* 
A grained lithographic stone is a little warmed, then the 
composition used tor rubbing in tint-stones, known to the 
generality of lithographers, mixed with an addition of white 
wax and a little copal varnish, is rubbed down with a piece 
of coarse short-haired flannel, or coarse cloth, until the colour 
becomes an equal brown grey. After this the drawing is 
either sketched upon the stone with soft lithographic chalk, 
or traced in the ordinary way with red paper. The lighter 
* Read before the Society, 10th December 1849. 
