SALMON — ON THE FORMATION OF ORE-VEINS. 
427 
With these Oleni there also occurs the Agmstus pmfwmis, a fossil 
which we have already noticed in the Welsh beds, and as character- 
izing the oldest Silui'ian schists and alum-slates of Sweden. 
We have also at Whitesand Bay, in South Wales, the Cambrian 
strata, overlaid by beds of flagstone containing the characteristic 
Lingula Davisii ; and we ought not to omit to mention that the white 
crystalline and fissured rock at Grantham, near Pontesford, in Shrop- 
shire, is penetrated by a vein of anthracite, small flakes of which are 
also disseminated through the mass. 
It is difficult at present to account for the occurrence of this sub- 
stance so commonly regarded in more recent deposits as of terrestrial 
vegetable origin. This ancient anthracite may, however, have been 
derived from sea- weeds, or indeed from land-plants, although no re- 
mains of such have as yet been found in these lower rocks ; or, on 
the other hand, its origin may have been due to accumulations of 
animal matter. 
GENERAL CONSIDERATIONS ON THE FORMATION 
OF ORE-VEINS. 
(Translated from the German of Professor Beknhard Cotta, of 
Freiberg, with an Introductory Notice on the Study of Mineral 
Veins and Metalliferous Deposits, hy H. C. Salmon, Esq., Plymouth.) 
(Contimied from page 396). 
VIII. Texture of Ore-Veins. — The varying texture of ore-veins 
referred to towards the end of Prof. Cotta's memoir may not be 
intelligible without a short explanation. We find that the two ex- 
treme textures of veins may be classed as (1) a compact texture, and 
(2) a handed or layer-like texture, both of these of course having many 
varieties, and passing into each other. The first is often characterized 
by a hreccia-textm'e, that is by containing fragments — often very 
numerous — of the neighbouring rock. The figure below shows an ex- 
