250 D. Mackintosh — Drifts of the Borders of the Lake- district. 



tained, an approximation may generally be made, and such terms as 

 post-Carboniferous, ante-Triassic, etc., miglit be used. 



If some such system were adopted, all the basic, augitic rocks 

 containing much iron oxide, would form one grouj), and we should 

 get rid of a number of useless names which have been applied to 

 rocks in utter ignorance of their mineralogical composition or 

 structure. 



Until quite recently such a suggestion could not have been 

 adopted, as there were no means of ascertaining with certainty the 

 constituents of the fine-grained rocks ; but now that improved 

 methods of microscopical research are available, it is quite time that 

 the unscientific nomenclature still in use should be supplanted by 

 one more in accordance with the present state of knowledge. 



III. — On the Drifts of the West and South Borders of the Lake 

 District, and on the Three Great Granitic Dispersions. 



By D. Mackintosh, F.G.S.i 



THE following is a continuation of the results of observations in 

 the Lake District and neighbourhood, made during the greater 

 part of last year, and the beginning of the present year. 



Drifts around Whitehaven, Cleator, Egremont, St. Bees, etc. — About 

 Workington, and farther south, the sea-coast zone of Criffell granitic 

 drift (described in last article, Geol, Mag., Dec, 1870, Vol. VII., 

 p. 564) is very narrow, but to the S. of Whitehaven it becomes 

 wider, and the great road from Whitehaven to Eavenglass, by way 

 of Egremont, very nearly delineates its inland or eastern boundary. 

 Boulders of this granite, along with porphyry (including the 

 tesselated kind from the Caldbeck-fells), syenite from Ennerdale, 

 etc., may be found on and in a red clay to the S.W. of Whitehaven, 

 where the ground reaches a height of more than 400 feet above the 

 sea, and is completely cut off from the Cleator and Ennerdale areas 

 by the deep pass which runs from sea to sea between Whitehaven 

 and St. Bees. On the brink of a quarried sea-cliff, about 300 feet 

 above Saltom Bay, the Permian sandstone is planed, smoothed, and 

 finely striated N. 30° E. 



On the way from Whitehaven to Cleator Moor I saw many 

 boulders of Ennerdale syenite, one of them measuring 5x3x3 feet. 

 On the E. side of the Ehen Valley, about 400 feet above the sea, the 



1 It may he desirable to give a short explanation of some of the lithological terms 

 nsed in this article : — Granular felstone, a fine-grained rock, mainly felspathic, with 

 uneven fracture, and graduating from light-grey (like the well-known Penmaenmawr 

 rock) to a colour nearly black. This rock has often heen erroneously termed both 

 greenstone and basalt. — Compact felstone, a felspathic rock with comparatively even 

 fracture, and often more or less flinty in appearance. — Felspathic breccia, a rock con- 

 sisting of angular or irregular fragments chiefly of compact felstone, generally from 

 one-fourth of an inch to two or three inches in diameter, sometimes much larger. 

 It looks like petrified pork-shop brawn. — Syenite, a rock (in the Lake District) 

 generally pinkish or reddish, and finer grained than ordinary granite, consisting of 

 felspar, quartz, and hornblende, or two of these minerals. It is always intrusive, 

 and passes into a rock approaching the character of greenstone. — Granilite, a con- 

 venient name for a very fine grained granite. 



